What about when it's on another site that you don't have access to? What about when it's a type of content that is relevant to you? This is hacker news so I'll assume you're involved in technology in some capacity - what if something like Stackoverflow was purchased by Facebook or Google and you couldn't view questions without a valid Facebook account?
You're seeing step 1 and not realizing that step 4 or 5 is the entire web gated behind walls.
There is no slippery slope. I'll object to step 4. StackOverflow is CC-BY-SA so I'm not that worried. If they try to change that, I'll kick up a fuss or whatever. It's not like fighting this will help with that. Wholly different audiences.
If there's no "slippery slope", then why do 3-4 companies control the entire internet today, when a decade or more ago there were 15-20 players? Go even further back and you had a myriad of choices; now Amazon, Facebook and Google have sucked up and shut down just about all competitors.
If you don't care, then you don't care. But saying there's no slippery slope? It's capitalism. It's happened with internet providers, it's happened with search engines, it's happened with social media, online stores, it's been funneling into a handful of companies for over a decade now. People want things for free and companies are willing to sell your data to finance their payroll. Saying it won't happen anymore is just naive.
There literally is no slippery slope because the CC-BY-SA stalls any slipping. You literally cannot lock away that content, and that license aligns StackOverflow's incentives with mine.
The structure of the Internet precludes universal locking away. I am confident in my ability and that of my fellow engineers to always have alternatives.
You're seeing step 1 and not realizing that step 4 or 5 is the entire web gated behind walls.