I'll play ball for a second but tact refers to context. If Rog had been caught in a split & drafted to get back on, then fine, yes. But that's not what happened. It's not the first time this season there's been an overly zealous decision by the commissaires either. Josh Tarling's own misadventure in Paris-Roubaix springs to mind.
I mean look, everyone can hide behind the almighty 'rule book' as much as they want but we all know it's enforced (at best) inconsistently & mostly not at all.
So yeah, great job 'commissaires' *clap clap here's your applause*... although I'd hazard a guess on Tuesday everything will be back to business as usual & no one will get punished for the usual 'transgressions' which occur at every point of a normal road race stage in cycling.
The context is that Roglic made a strategic CHOICE to switch bikes so he could have an advantage later on. The downside of a bikechange is that you need to get back to the peloton, he drafted back behind his own team car, negating that downside. So that's the context. What's next? A TT where some riders change bikes on purpose and they just take the lost time back while drafting?
Also the UCI has been giving out 20s penalty's for drafting pretty often this year, this was so blatant that you just knew he was gonna gat one.