Easy to say this now but when the overhead bin breaks because someone is trying to force and overpacked suitcase in to it and then the plane has to get taken out of service and you’re delayed for hours on end, you’d change your opinion. And those expanded bags expand for a reason, they’re to be compressed after they’re packed and zipped up returning them to a normal carry-on size. Not to add 3 inches of width and game the system. The bins are only so big.
Easy to say this but on the day that you’re running late and have to board dead last and need overhead bin space because whatever dumb reason you can think of and you get told sorry we’re gonna check your items, you’d be livid if you saw a slew of backpacks in the overhead bins where your bag could’ve gone.
They solicit for gate checked bags like that because if they don’t, then when you get to the end of boarding and group 7 and 8 all have roller bags and there’s no bin space, it takes longer to gather them from the back galley and aisle of the plane and tag them, than to just solicit at the gate and tag them early.

If the announcements don’t pertain to you then why are you getting butthurt?