Devil's advocate:
1. Even if villain didn't realize the game change right away (which I agree can be difficult sometimes online) there is the fact that he is not leading on fourth street on (not to mention the initial bring-in). That should be setting off alarm bells in his head about which game he's playing. OP is of the opinion that villain isn't a complete newb and knows how to play somewhat decently. That's on villain for not paying attention to not only the game change, but the action in the specific hand he's playing in. That's A LOT of info to be missing/ignoring, and I don't know if it's really up to hero to point it out.
2. On fifth street, villain has two queens showing and hero has 7h8h5c and is just pumping the pot up. I guess hero could have a made straight already and could be chasing a flush draw too, but villain has to question at some point why on that board hero continues to raise it. Hero might not just go crazy with a straight and/or flush draw when villain has a pair on the board because even if villain only has trip queens at this point, he still has outs to a boat if he doesn't already have one. So again there's even more information that villain should be considering that he did not.
3. It's online and it's definitely different than a live game. Playing online, I'm probably surfing the net, playing other tables, talking to my gf, eating a snack, completely ignoring the chat box, etc. I honestly might not even realize that he didn't notice which game he was playing.
I'm not saying that I wouldn't have said something, but there are some other important points to consider.