>Forming an opinion based solely on the title or the (perceived) author's bias without ever reading the content is a problem no matter where you stand.
First impressions matter. A job posting for an elite JavaScript ninja with 15 years of ES6 experience is going to have the creator of the job post judged very harshly, even if no other information is viewed. Sometimes that will be wrong, but it will be right often enough to be reasonable.
As for this particular case, an analysis of how they calculated the number has already been done by other who have posted under this same article. If you feel there is a flaw in their logic, you can reply to them directly.
>How is this different from anybody responding to a comment solely by attacking the person who wrote it and their political affiliations rather than attempt to discuss the actual content?
Because it is based on both the author and the content, and the nature of the disagreement is that the content is wrong for reasons that are only incidentally related to the author.
The argument isn't 'study is bad because author is bad. The argument is 'the combination of the author's own stated goals and the creative statistical freedom taken when calculating the figure leads me to believe there is significant bias in and behind this'. There is also a known issue of political groups injecting favorable bias in the work they do.
>Would you question a reply like "Please keep in mind that this opinion came from [a member of party X] / [a supporter of cause Y] so I don't think their opinion is neutral [period]" to one of your comments or remarks?
Well, I don't think any opinion is neutral (at least on matters of politics) to begin with and would overall trust someone who recognizes their biases more than someone who doesn't, even if that is stereotypical of me.