In the defence of F1 the cars get most of their grip from downforce, when they run slow in the wet they just have no grip at all. The cars are not built to run int he rain as it's the least likely weather conditions throughout the year. 2 wheeled is all about mechanical grip as aero has little effect on bikes.
I'm annoyed it's red flagged but no amount of "man up" comments will make me think they did the wrong thing.
Nick