If it has a paywall, why would I tip your post sats? I have to spend that money on the paywall. Even more insulting when its a FIAT paywall rather than a lightning enabled paywall.
Twitter has also blocked content for people who don't have Twitter accounts, but if you have a Twitter account, you probably follow these posts already anyway, making your SN link to it spam for non Twitter users.
This has been my opinion on what I think should be added to the definition of "spam" and why I will ignore a post you probably think is pretty good and under other circumstances would get a zap tap.