Hello,
First of all I don’t really get the actual meaning of “please”. I understand it as it used to make a polite request. However I have rarely seen any westerner saying “please” on either Lemmy, Mastodon or IRC. where I live using “please” (मेहरबानी) is used often.
Much more likely they’re saying ‘thanks in advance’ in the original post or otherwise they reply with gratitude for useful replies and answers.
If they don’t, then yes, they’re probably immature, a 14 year old or just a twat.