It's very valid to sell premium blocks/packs. It's really amazing to have all the rest in the MIT version open-core. Thanks for that and don't be demoralized by some comments, we don't all think the same.
A proprietary software house that releases some free software is still a proprietary software operation.
Kudos to the team of total.js. Who cares if they offer some paid stuff; because of the MIT license anyone can. If they don’t do it, someone else can and offer it all the same. As long as vital parts remain MIT, I cannot see how this is a proprietary software operation.
Tl;dr I agree with you, but I don’t see that being the case here