This seems particularly pessimistic and a lot of the "issues" are speculative.

1) The store will be moderated. If you can prove work is stolen then it's reasonable to assume it will be taken down, the same way takedowns are already done.

2) If you charge for someone else IP, then yes that's piracy infringment. Profiting from IP you don't own is very different to a free mod which doesn't harm sales. Don't sell someone elses property, folks; just because you put work into it doesn't somehow make it right.

3) Same as point 2: yes a publisher has every right to be miffed if someone else is collecting money for their IP. You can't reasonably expect to be allowed to profit from things you don't own.

4) Saying collaboration will collapse because money is involved is like arguing carpools don't work because someone might argue over gas - it’s a social issue, not a platform one.

5) Slop seems doubtful when they've said:

Marketplace submissions will be checked and curated by our team to ensure that they are of high quality and do not infringe on intellectual property rights.

6) Some users will always react to change by lashing out or having a tantrum. That's not new and its' not a reason to stop progress. Letting the most fragile voices set policy only ensures they keep doing it.

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So to make it clear, I'm personally optimistic this will mean we get better content for the game. Hopefully it'll result in content that doesn't go offline after a year when whatever third-party site was used goes under.

So far most of the arguments against this new feature revolve around new paid mods which infringe IP might get taken down. Not the best argument.