Why do we have a problem saying "false teacher"?

I've recently watched American Gospel: Christ Alone. It's particularly focused on the Prosperity Gospel and is a documentary designed to call it out as false teaching and those who peddle it (often for profit it seems) as false teachers. Numerous solid American pastors and theologians are on screen explaining the deficiencies of this false and dangerous 'gospel'. It's a moving, intelligent and high quality bit of documentary making. If you can, I think it's worth your time to watch, even if you're in the UK. Our situation isn't the same, but pastors among you will know full well both that these false teachers have a long reach onto the screens and bookshelves of the UK and that evangelicals in the UK have repeatedly been tempted to peddle something not so dissimilar, if less blatant.

One of the things that struck me though, was that there was no fear of calling this teaching and those who peddle it out. I was struck, because it seems to me that, in the UK, evangelical leaders are wary of that. I can think of various discussions, online or off, where someone has been criticized for trying to show up a false teaching or naming someone as a false teacher. I've had conversations with ministers who would say something along the lines of "of course we won't invite X to come and preach, but we won't say anything public or make a big deal of it." In my background, in Anglican ministry, this has often related to those in the hierarchy well-known for their liberalism for example. I've read in a book (supposedly encouraging Christians and ministers to stand for truth) criticism of a minister naming someone as a "viper" (which is quite a biblical way of describing false teachers!). Why the reticence?

I think there are some good reasons to be reticent. Let me suggest three:

1. We don't have the facts. In lots of cases, I might be quite suspicious about what someone believes and teaches, but I don't necessarily know. I can think of a case where I suggested someone was a false teacher on the basis of what I had been told they believed. Now I did it reasonably carefully (it wasn't public, I expressed some surprise if it was true and I noted my source), but it wasn't true and it's important to know the facts - not just secondhand.
2. We may not be sure. Some people are hard to pin down in terms of what they actually believe and teach. It may even be the case that we think that they were wrong, but that they are now revising or have revised their views. Now those situations can be concerning and confusing, but they may make me reasonably hesitate. I may express some concerns etc., but I might not want to go the whole hog of calling them false teachers.
3. We have no connection to the situation. I think there may be good reason not comment on people or situations that are not relevant to me. So, if there is a false teacher on a different continent with no significance in the UK, it is probably unnecessary to call them out in my situation and if I am are doing it may indicate a tendency to want to be calling people out all the time!

However, too often none of those things are the case. For example, it is someone in our denomination or circles, who has clearly written or said things that are anti-gospel and those thing are easily discoverable. This leaves us with poor reasons for not speaking up.

1. We're timid. This is the warning Paul gives Timothy in 2 Timothy 1:7 in the context of standing up for the gospel. If we're pastors, this is not acceptable. Part of guarding the deposit of the faith is to stand up to false teachers and their teaching.
2. We don't want to appear negative. There is something in this. The pastor who is always on the look out for someone to criticise has a problem. However, the Christian message is not one of positivity, although it is immeasurably good news. I'm reading Jeremiah at the moment and it's pretty obvious that sometimes the message has to be a tough one! Jesus and Paul are no different.
3. We fear the backlash. Maybe in our congregations or our circles it won't go down well to call out a particular teaching or teacher. If we put our head over the parapet, it may well be shot at! We start doing trade-offs, if I don't call this out it might give me the chance to disciple X and of course once I've done that they will see it in the end. This is a little like reason 2. If I just teach the positive, I can avoid the negatives and they'll become obvious. But it's not biblical. In the end, of course this goes back to reason one - we need courage not timidity.
4. We fear the relational fallout. Perhaps this person is a friend or colleague - we've always liked them and maybe they've helped us (perhaps we even think we can influence them back to the truth). Perhaps they are significant within a denomination or grouping that we are part of. Again we can think of the fallouts Jeremiah had and the consequences he faced. Or we can think of the difficulties Paul addressed with people who had been co-workers or even the apostle Peter. Again we need courage to endure the consequences, not timidity.
5. We fear the personal consequences. Perhaps to speak out will mean we won't get the ministry posts we desire. We'll be thought of as difficult. Denominations or networks will perhaps thwart our plans to plant churches, start new ministries or appoint new staff. We may even lose our positions and so face significant financial and personal costs. We can even phrase these things in terms like "for the sake of the gospel..." or "for the sake of my family..." or "for the sake of my ministry..." There's all sorts wrong here, in that we're dressing up personal gain in ways that our conscience can find palatable.

I'm sure there are other possible reasons, but if we're really falling foul of these five bad reasons then we are saying we are not fit to be leaders ourselves. Worse, if we believe  2 John 10-11, we may essentially be part of that false teaching network ourselves!