Black Knight Irios
Explorer
There are all these builds I see citing wintertouch / lastingfrost as working with frost weapons and yet the feats themselves say "powers that have the cold keyword." If they didn't work with melee weapons that would be more reasonable.
I don't see your problem, is it:
A: You don't believe that by RAW those 2 feats work with a frost weapon?
or B: You don't like the fact, that they do?
If it is indeed A: there is nothing tu argue the rules are clear.
But if it is B feel free to houserule that in your campaign those feats only work with powers that have the cold keyword build in or whatever fits your taste.