Logical fallacies they may be, but often true none the less. People who's profession is 'scientific' are still people. Despite being termed 'Scientists' and their research being accepted as 'Science' they often get emotionally involved in what they are trying to prove (like the professor of microbiology I had who had "proved that it was not possible to cook a turkey properly if it was stuffed" because he'd measured the internal temperature of a bird his wife was cooking and it never got above (I think it was 90C)).
More logical fallacies. On that basis we cannot believe anything Christians say. Christianity says don't murder and don't steal and don't commit adultery but some Christians do kill, steal and commit adultery. Therefore nothing Christians say can be believed.
See the fallacy?