The links are set to nofollow because search engines shouldn’t follow these links: they’re not real pages, they’re just placeholders before each Social Network is loaded. Here is what Google has to say about nofollow links: Use rel=”nofollow” for specific links
Here are some cases in which you might want to consider using nofollow:
- Untrusted content
- Paid links
- Crawl prioritization
“Crawl prioritization” is relevant here: Search Engines can’t share your posts on Social Networks, so there’s no reason to invite Googlebot to follow these links. Using nofollow on these links enables Googlebot to crawl other pages you’d prefer to see in Google’s index for your site. There’s no way to change that, so I would ignore those SEO warnings for the sharing buttons as they won’t have any impact.
I hope that clarifies things! Marking as resolved.
