As for how family history researchers are viewed, I think it is variable, and there are some good reasons for why some priests/parishes may be less than keen to help.
In the first place, both my father and I have seen mutilated parish registers, with missing pages which were very clearly cut out, by memento seeking visiting "researchers". Another point is that interest in family history research has exploded, and dealing with requests could become a distraction from their primary mission (the cure of souls, as it used to be put).
That said, others are into history themselves, and delighted to help. For example, 20 years ago the then parish priest of Oulart was the editor of a local history journal, and extremely helpful. All depends on the person, and we made some effort to talk to the priests involved. I think being local helped a lot. Finally, as my experiences with personal visits were almost 20 years ago, I can't really comment on the situation today.