Yes. I do know people who think like that or who have thought like that. I think if someone wanted to make Steemit on the Bitcoin blockchain or sidechains it would be a whole lot of trouble compared to making a new blockchain.
Juan's case is a bit more measured. Later in the interview he mentioned how most "Bitcoin maximalists" or strong Bitcoin supporters, will normally have a few altcoins that they believe are good projects. The idea is to support the strongest project, avoid dealing with scams for the most part, and encourage other projects to follow Bitcoin's strong example.
Personally, I don't agree. I think the Bitcoin developers are focusing on the wrong things - trying to build an amazing lofty Tower of Babel machine when there are people out there who could benefit from this technology now, if it only had a decent user experience.
I'll have the full interview up in a couple of hours if you want to hear the nuance of Juan's position.
Edit: the full interview
Yeah, he seems reasonable, and encouraging actual projects instead of scams I totally agree with. But that's not really exclusive to Bitcoin maximalism, it's just common sense.
Yes, user experience needs improvement. Sending and receiving with wallets isn't too bad, but acquiring crypto on exchanges, etc. is a big barrier for most people. This is another area where Steem has a major advantage. It's already set up for mainstream adoption in many ways, because there are many ways to earn it without having to deal with exchanges. A total noob can do it as long as they figure out how to build a following and get upvoted, which is something that a lot of content creators have experience with already.
Looking forward to watching the full interview.