Well yes? The platforms only accept certain resolution/bitrates and also most of America isnt running 1gig up. They're running 5-30 mbps up. So yeah they need to encode it.
Do you not have 98% high speed 5G coverage?
You also will need _some_ sort of encoding locally before uploading, even if it's minimal, which could lead to issues when encoded again (although there are codecs available to minimize this).
Leaner delivery is not just ethical, but it also makes better business sense.