That's certainly reasonable. But this does not mean you should ignore fallacies either. Usually when I see people talk about fallacies it's part of a point-by-point rebuttal against some post--you refute some of the points in order, perhaps agree with others and also point out any points that are actually fallacies. I think this is perfectly reasonable, but I can also see how solely pointing out a fallacy would usually not be terribly useful.

Also, ad hominem is a special case: not only is it a complete fallacy but it is also often quite rude. Minimizing personal attacks is important in keeping discussion pleasant and civil even ignoring their logical implications.

If I could only have one rule for some discussion forum, that would probably be it: no personal attacks.