"This music is so corny and weird."Of course it is, but that is part of its charm.
We're talking about the Atlantic mirror image to, say, 1910 Fruitgum Company, Archies, McCoys etc, 70ies glam teeny bop was Europe's answer to US bubblegum. It followed a recipe: loud drums, catchy sing-along choruses, Rick Nelson type guitar riffs, lots of harmony double-tracking of lead guitar lines, a certain "fairground merriment" in the (often overblown) arrangements and the instrumentation, novelty lyrics that picked up on teenage slang, but didn't really attempt to make sense. As teeny bopper music often is, glam rock was actually quite retro, the actual hit factory songwriting was firmly planted in 50ies and 60ies rock'n'roll and pop, even Doo-wop craft. BTW: Qualitywise, Kenny were certainly at the bottom of the heap even as glam rock goes. (BCR's group performance, otoh, was underrated IMHO - lost behind all the tartan crap and girly screaming. I'm with Joey Ramone who liked them too!)
Smokie, The Sweet, Mud and Suzi Quatro all had the same songwriting and production team (and sometimes the same session cracks playing on their singles) as did BCR and Slik (the Slik song posted above was initially slated for the Rollers and you can sure hear it!).