Not true.If you're not a drummer you really shouldn't comment
I am not a blues guitarist, but I still have the right to say that Eric Claptrap is less important to the furthering of the blues tradition than Captain Beefheart.
We can have opinions and share observations on Pink Floyd even though we are not in the band.
We can be passionate about flashpoints around the world even though we are not a soldier or politician.
If you ARE a drummer, then in this circumstance you are better placed for sure to enlighten us with your inside knowledge but you have no right to deny us our own comments.
Critics, as well as artists, can also be a good thing.
I've met plenty of musicians who think they can play or that they know their stuff when in reality their knowledge is limited and their playing is mundane and average, albeit technically proficient. So, even if you play the instrument yourself it still doesn't necessarily mean you are a better authority than a non-player.