Seriously, people will never learn. People who crap talk you because of HPS are stupid.
HPS is a horrible way to rate healers if you're not looking at the entire big picture which is pretty hard to do completely. This is why shit like World of Logs rankings are so retarded. There are so many different variables that affect it, like who takes damage how and when among many other things that aren't in the healers hands. Also, some raids just take less/different damage for a myriad of reasons and this could make your HPS look low or high. The raid make up and who you're healing with can change your HPS constantly also.
The main thing they should rate you on is...
1) Did you go OOM?
2) Did anyone die?
3) Were people constantly dipping dangerously low and then staying there for too long?
Things like that. Practical things.
So without looking at the big picture, HPS BY ITSELF is not a great tool to measure a healers contribution to the raid.
If you want though, use World of Logs next time, upload the log, and link it to them, if you're a decent player, you'll see that you contributed just as much or more than than the other healers.