As you know, I do it, but since someone said rewriting was plagiarism, I've been sure to link to a source. You're right though, news outlets do it all the time. They use press releases, which don't require citing, and news agencies, who probably don't care either. This is probably written into the agreement with the news agency.

I've just looked up Medium's definition, and I think it probably depends upon the degree of rewriting. They say "paraphrasing and slight re-writes" are "mosaic plagiarim".

I've seen articles removed from Medium for being rewrites that sailed too close to the original, without citing the source.

https://help.medium.com/hc/en-us/articles/360041640213-Plagiarism-Guidelines