Nope, still don't see the issue
OK so some interoperability may be nice with regards to images etc. not being sent via SMS/MMS... Apple could do this (and probably should) and give them a different colour bubble. People would then just complain that the bubble is still not Blue.
If Apple were to release an iMessage app, would this really solve the problem as then Android users would then need to download another app and they would moan about this too (or about yet another bubble colour).
Google Chat is already available on iDevices so effectively Apple don't need to create an app because there is already there, so is the Representatives complaint still valid about loss of quality, location etc. in images? Seems more like he is moaning that Apple people don't want to install another app that resolves this issue, probably because so many are already using other Data Gatherers messaging services already.
I'm on Apple (my choice), the kids on on Android (their choice)... i couldn't care less about bubble colour, image reduction and location within as we use the app most appropriate to the use case. This is sometimes SMS in crappy signal areas (yes, there's lots of them, yes itis not e2ee but use case remember), Facebook Messenger (with e2ee), Google Photos (rarely) or Discord. The kids sit a lot of time in Snap due to its functionality (I don't have it).
Not kept up on it but, has Google opened it's Rich Test messaging service to others yet? The Carriers were all up for it at one point but is it actually available? Maybe this system should be focused on rather then than chase each individually. Though if it's not e2ee by default, then I wouldn't care less again.
My argument here really is, there are ways around it, those ways are probably used more anyhow due to what the user is trying to achieve, so does it really matter.