Is it impolite to message members from the People list?

I wouldn't say impolite, but your responses or lack thereof might give you that impression. probably good to pay attention to the introduction messages

youngguy88 if it is constructive and meaningful and not offensive what harm is there either they will answer you or not

I tried it once and didn’t get any responses. So I stopped. Now I just scroll questions

I dont mind if people message me from the list. Sometimes you might make a new friend.

It's more acceptable if you're friends.