You’re partially correct, older bikes didn’t have catalytic converters. Compliance with Euro 5 means all new models past… 2018 I think, must have one equipped.
As for noise, 75db is louder than a modern car, but we don’t have room onboard to dissipate a lot of the sound energy like a car’s long, standing-wave tuned exhaust does.
I don’t have a car, just a bicycle and motorcycle. I like them both, though I trust my bicycle more when there’s a blizzard.
P.s. I also like fortnine videos, he’s mostly correct (though dead wrong about physicists being the grownup version of engineers) but look at the data for yourself. Keep in mind all these values are far, far lower than they used to be. We shouldn’t stop striving for better, but we should keep things in perspective too: bts.gov/…/estimated-national-average-vehicle-emis…