The advice given is partisan:

So check before you leave the polling booth, and if anything is wrong, get it corrected immediately. Report any irregularities to your local
Democratic headquarters.

What if they reported a Democratic irregularity? Whaddya think would happen to it?
Also, snopes offers two possible explanations for the incident. The shorter one is posted here:

When pressing enter after marking a straight-party vote, it appears that a handful of voters have inadvertently turned the select wheel to
highlight the first position of the presidential race and then hit the enter button, which selects or de-selects the first position.

Did you miss them when you read the article?