I am quite frustrated about something

I tried to go on the exchristianity sub, and all I asked for was a respectful conversation with the members so I can hopefully try to answer questions and whatnot. Those posts were immediately removed by the moderators with no explanation yet people get to be outright disrespectful and ignorant, acting like they know it all.

How can I reach these people and try my best to help them ? I really just want to help, as a 15 year old Catholic dude.