Nobody questions that arXiv is a publisher. They even have a moderation. Preprint publishers are not peer-reviewed publications, arXiv does just basic moderation and requires registration to sumbit. The emergence of low selectivity megajournals like Nature Scientific Reports and their low quality of peer review, blurs the difference in the low end.

IMHO arXiv is in par with "Nature Scientific Reports" as credibility goes. That does not mean arXiv is peer reviewed publication. It means Scientific Reports is not proper peer reviewed journal either

https://info.arxiv.org/help/submit/index.html

>All submissions are subject to a moderation process that verifies material is appropriate and topical. Material that contains offensive language, non-scientific content, or is plagiarized may be removed.

An open letter regarding Scientific Reports https://deevybee.blogspot.com/2024/10/an-open-letter-regardi...

Cleaning up "Scientific Reports": Can It Be Done? https://www.science.org/content/blog-post/cleaning-scientifi...

That is a link to their editorial board.

Seems logical that they want to ensure the quality and therefore go through some steps, including moderation and author vetting. Not sure why this would be “masquerading”.

They spell out their guidelines including moderation here: https://info.arxiv.org/help/submit/index.html