Re: Am I a terrible drummer?
Not sure what your long term goals are...but...
The question re: your drumming skills is irrelevant.
The question is, how do you respond to negative feedback?...accurate or inaccurate.
If you do not respect the source, ignore it.
If you respect the source, explore it.
One of the difficult long term learning skills re: drumming(or anything else) is how to learn and persist.