In my head, there's two explanations to reconcile that one.

One is Spinister is actually really lucky - he stumbles onto enemies, blows them away out of shock / fright, and then everyone assumes he's a brilliant killer (and Decepticon propaganda is only too happy to spread the fear of Spinister as conveyed in his bios).

The other is there's another guy out there named Spinister who actually is that dangerous, and he's not happy that his name got assumed by that loser Whirlygig.

Ultimately I just enjoyed the stories for what they are, but there's some latitude for different explanations of how characters diverge from their traditional incarnations.