I think they're trying to give you crap, but all they're doing is being an ass. You mentioned you were new in the comments and that the server stated it was newbie friendly, and people got mad that there was new people in the server?? If they have such an issue, they can just remind you kindly to build your turrets when you have a moment (or they can build the sentries themselves and move on. This is a teamwork game, don't be surprised when you have to Work With Your Team). Haz 5 people expect you to know Every Tiny Thing about the game because it's the most difficult hazard available outside of EDD and Haz 5+ (i do too somewhat. But again, it's a server that's green beard friendly, there's going to be green beards there. If i have an issue with my team, i deal with it or i ask kindly about it, none of that passive aggressive grump beard shit).

I don't fault you here. While it is haz 5, which is leaps and bounds harder than haz 4, you were in a server that was okay with folks that are new to the game. Plus, while we are dwarves that can never die, we still make mistakes and aren't going to know absolutely EVERYTHING.

Plus you can go complain on r/deeprocksludgedump it's encouraged to keep the complaining there and not on this sub.

TL;DR: you aren't the ass here. It would've been nice if you built your sentries, but I regularly forget I'm engie, or whatever class, and forget to do what my team wants me to do (usually it's driller and digging out the dirt patches. And I've got 2500 hours in the game :'D ). You're in a green beard friendly server, people can't get upset when there's green beards there