Exactly this. It's not too hard to think about the intake of random requests a popular team may receive. Even code reviewing a patch from a separate team carries its own set of eyes, which is still work for the team. There's a ton of context OP is probably not familiar with and walking them through all of that baggage is not worth the effort. While this may seem annoying from an outside team's perspective, it's the only way to really focus on their roadmap and be able to commit to scheduled work.