why do the author's politics make a difference?

In this case it makes a difference because there has been an alarming increase in harmful lies made by the far right. This is a purposeful spread of misinformation that many people hesitate to get involved with in any way, and for good reason.

I do not trust the creator of Brave to be aligned with the far right and to still be guided by ethical conduct that I can trust. If you align yourself with people who lie and put others in danger for profit and control, you're condoning such behavior and may be capable of it yourself.