I've never seen an "aggressive" player injure himself, only others. And I've never seen a BB, GM, or EGM suggest that aggressive players injure themselves. I've never seen anyone suggest that actually, except for you in this thread. But I haven't done extensive reading on it so I can't say for certain.
I will say that logically it doesn't make much sense to me. And it does bring up another point for me, personally. I think that playing against aggressive players is what causes more fouls which leads to more chances for injuries to occur. So... how would that be the player who got injured's fault? How should that affect his market value at all? There is no such thing as an "injury prone player", imho, so there's no possibility for dishonesty in selling a player who has been injured.
Basically, no one thinks like you do about this, so no one can be dishonest about it. And even if you were to sell a player you thought was "injury prone" without offering a discount, thinking you were being dishonest, in the real world it has no effect because the thing you think you're being dishonest about doesn't exist.