Does having double kicks, make your single pedal technique bad?
No, at least not for me. I can play just as well with either foot. Well almost, the left still has some catching up to do
I played in a metal band when I was younger, so I spent a lot if time working on double bass. After awhile I moved on & grew into other types of music. I still have the chops on the double (although not quite as fast as I was back then), though I don't really use it quite as much. I never used them as crutch though. I feel like its an advantage over drummers who never learned it.
If you can play it with one, do it! When the tempo gets beyond your range, use double-pedal!
There seem to be some who really hate fast bass drums, which is fine. You can choose not to use it & not have it in your music, but don't accuse players who do of cheating, or hiding poor technique. For those who do use double kicks, that's great too. The best ones are tasteful, creative, & can play just as well with single or double bass.
A good many drummers don't really utilize their feet to full potential. What has already been stated such as cowbell, double hi-hat patterns, keeping a groove with your pedals while soloing on top. The possibilities are endless, you just have to be creative to use double bass or multi-pedals in way which is complementary to the music, & hasn't been run into the ground by other drummers for the last 40 or so years.