I see. Yet we have 2 Timothy 3:15ff and 4:1ff that teach us how to handle such issues which you should follow and uphold. You are no different than others in the church who are called to uphold these things, as I am fairly certain you know these passages and also Jude 3.
That said, there is never a right place or time for them to preach their false doctrine. They are to be opposed as Scripture mandates. But what we see these days is apathy, cop-outs, timidity and shirking of responsibility. Not one of these stances is Scriptural or Christian yet many today think doing these things is being Christian and peaceful when it is actually unChristian and instead of being peace it is appeasement toward doctrines of devils.
You probably aren't speaking of government regulation when you say they shouldn't be allowed to preach anywhere, but I do believe they have a right to preach in their own circles and to outreach as they desire as much as we do. In the eyes of the government, that is; if freedom of religion is to be preserved, this must be so. Otherwise we give the government power to regulate not only non-Christian religions, but Christianity itself as well.
That's dangerous. But as I said, you probably aren't saying the government should control it.
Jesus' parable about the wheat and the tares applies here, IMO. We don't have to promote or agree with others' positions in the slightest, especially if they are indeed unBiblical, but we can't oust it ourselves either.
Teaching and rebuking in faith and love I totally get--doing so forcibly, just no.