Not really. Either my explanation is wrong or theirs is. Honestly could be either.
There’s so much misunderstanding and misinformation around torrenting.
All I know is that I’ve never had any problems downloading without being connectable. Never ever. It’s just not an issue.
Additionally, the vast majority of people torrenting in 2023 are using a vpn and none (very few) of them will forward ports so it can’t be a big deal.
Thirdly, there’s a lot of piracy purists / elitists who just can’t abide the idea that your set up may not have the best possible configuration for seeding. IMO, seeding on a residential connection is just a waste of time - download on a residential connection, seed on a VPS / seedbox.