There are certainly plenty of rude and misguided people in the FFXIV community right now. But there are also a lot of great people around, too Hopefully you come across some regularly.

The devs should really keep in mind that they have the power to guide the community in subtle ways through the game mechanics. Like with the issue OP mentioned, where lowbies can't get exp if you're too high level and you heal them. This is a game mechanic that doesn't encourage a helpful, trusting community.

There are plenty of ways they could change this. For example, your healing power could scale down to match their level, so it isn't too overpowered when you heal them. And then they can still get exp from their kills without it being too cheap to have assistance from a highbie.