So, if I keep my cold storage coins in a legacy address, how does the affect anyone but me?
Attacking segwit isn't going to accomplish much at this point anyway. That battle was already fought, and the pro-segwit side achieved a decisive victory. I agree that any negatives about segwit will remain big blocker talking points, as they try to make BTC look weak. That doesn't mean there aren't still legitimate criticisms of segwit, and lightning, for that matter.
I agree with this with the caveat that 'legitimate criticisms' are one thing and fud another. Basic game theory indicates a extremely low probability that miners would attack and destroy long term gainz for short term gainz. Because that is what would have to happen for such an attack to be effective. The entire crypto ecosystem would have to collapse permanently...not just bitcoin. Everyone would lose faith in decentralized stores of value.
Now could there be and are there bad actors? Maybe...but imo simple extrapolation indicates a zero sum game for this attack vector.