Ignoring them means not letting them influence your opinion either way. You should still allow yourself to reach the same opinion they're espousing by your own means, otherwise you're letting them control your opinions just as much as somebody who slavishly agrees with them.

Ignore the boy crying wolf, but you should still watch for wolves. If you don't want to, fine, but "I don't look for wolves and my sheep are fine" is not a very good argument.