But, regardless, blocking any registrars that size the way you’re describing would break way more businesses and hurt the recipient provider’s own reputation.
Yeah I thought that too but when speaking with the email admin that was blocking Namecheap while figuring this out they had already decided it wasn't worth trying to allow the 1% of valid emails vs the 99% spam emails they felt they received via Namecheap domains.
This honestly starting to sound more and more like a smear campaign
Smear against whom? I'm a Namecheap customer, just relaying my own experiences using them. Besides that quirk I like them fine as a registrar.. I know it sounds dumb but I even renewed my domains there even after those email issues.
It's fine, you don't need to believe me as I said it's just my own experience using Namecheap domains for emails. But you could just google around, you'll see plenty of people discussing Namecheap & looking for solutions to block them (or solutions to successfully send emails with hem).. it's not something I randomly made up if that's what you're implying.