They consider it dangerous. It is a threat to them because this ability is unknown to them and is totally beyond their belief system. It wasn't taught in school so it can't be done. They defend their position by attacking the unknown. This is natural.
Every profession does it.
People want to be right. They don't like their beliefs threatened. Not every case runs smoothly, of course, but the vast majority of them are handled quite easily in one session. This is perfectly evident on the EFT tapes and many of you have experienced it already. The process is relatively painless and the result is usually long lasting.