Caught in a Petty Office Drama

So I started at my new job last week as an intern at this big marketing firm. First day was okay, some of the senior folks are super friendly, but there's this one guy, Steve, who seems to take any chance he gets to be a real buzzkill. Anyway, today we were doing a team meeting and had to go over some new client guidelines. I was kind of excited because our boss mentioned it might involve working with another department on an upcoming project. Now here's the thing, during the meeting, Steve kept whispering under his breath about how this is all pointless since the other department is full of slackers and knows nothing. Needless to say, my spirits were dampened as I tried not to let it get to me. By the end, I was already bracing for any bad news or more negativity. But then something weird happened: during lunch break, one of the team members who works with that other department approached me and asked how things went in our meeting. They were really interested in finding out what we discussed because it could impact their project too! It felt like a small victory just being included since Steve made it seem like the whole thing was pointless. But then I started overthinking everything, wondering if maybe I shouldn't have been so silent about Steve's comments or if telling someone off would've helped. Part of me thinks I'm reading way too much into this, but honestly, his attitude towards collaboration is kinda stifling our team's potential to work together more effectively. Now here’s where it gets really embarrassing: right after lunch, I accidentally let slip some snarky comment about Steve being the one who knows nothing and just wants everyone else to fail. It wasn’t a big deal in terms of actual impact, no one seemed phased by my little outburst. But now I’m feeling this weird mix of relief that it’s over and guilt for kind of ratting him out, even if indirectly. So here's the confession: should I be worried about making waves or is there a point to calling someone out when they're dragging everyone else down? Am I just being too sensitive or could Steve actually be causing problems with inter-departmental cooperation? What’s the right thing to do?