I don't know if this fits the actual definition of a cooler. Let's not get into that though. Did he flop bingo, considering the hand that he's calling a raise with here? Absolutely! Could you have gotten away from it after the flop? Maybe. After all, there are couple of hands that could have gotten there on the flop and a quite a few donkey hands that could be drawing. Would I have gotten away from it? Maybe not.
What I would really be interested in is knowing the exact pre-flop raise and reraise amounts. I've become accustomed to seeing some pretty "loose" calls, especially with suited hands. I'm generally not going to be calling a raise of 3x or more with 9-10 suited, unless I have a reason to think someone is trying to make a move. I'm definitely not going to be calling 3-bets with it. But how truly bad of a call this is would depend to me on the actual size of the bet being called. Some players are just looking for an excuse to play hands, like having suited cards. Our bets, raises and reraises should be sized to give these players a reason to fold.
What I find is that once a player makes their mind up to call, it's going to take more to change their mind. For example, it's going to take more than a min raise to get me to fold 9-10 suited from the BB, but I'm not calling more than that from an EP raiser. But to someone with a wider range than me might consider 9-10 suited to be a stronger hand, epspecially from the BB. Once they make up their mind that they like their cards, a min raise, and maybe even 3x, isn't going to change their mind, especially at these low stakes. Once they've made up their mind to call the first raiser then it's much easier for them to call a 3-bet. It's almost as if their thinking goes from "I want to play this hand" to "I don't wand to fold this hand", which is a major difference. We need to take this kind of thinking into account when sizing our bets and raises.