@jonpainterphoto @ArisuGunpla @aral @boyter This argument is quite misleading if you omit the important concept of fair use.
If it were necessary to get explicit permission to copy social media posts, then no social media platform would be possible.
This is true also for the web in general: if someone visits your website, you can't claim copyright infringement if its contents are downloaded.
The DCMA provision is there for content that the poster does not have the copyright in the first place — and therefore fair use does not apply.
If a site aggregates public social media posts, while preserving attribution, this clearly falls within the fair use scope.