First of maybe if it was Adarsh i would have thought the reaction was over board. But this si Krishna's personality so it totally makes sense that he would kill any other man who looks at Pratigya in the wrong way.
As for Pratigya..apart from wtt we all think abt her individually Pratigya and Arushi are shown to be very pretty WHITE skinned girls. As far as I know back in India white skin is considered very good and this point has been made very clear so it makes sense why Radhe chose to mess with her.
And another thing is that the kind of uneducated ppl they are, they prolly get most of their girls from villages like Kesar so obviously makes Pratigya look classy and attractive from thr POV.