If you think the two are unrelated you're oblivious to the considerations that must be taken into account when discussing potential privacy concerns in software. It's not ad hominem to acknowledge that the personal convictions and values of the CEO (and indeed other employees) can potentially decrease the sense of privacy of a product.

If the CEO is so adamant in his anti-X stance that he decides it's acceptable to censor access to materials about X, or perhaps worse that he decides to expose anyone using his software that discusses or supports X, would not consider those valid concerns?

Companies are made of people, and software is made by people. Since people are not neutral, companies and software are also not neutral. The stances of a company or software on privacy, freedoms, etc are all influenced by the stances on those exact issues by the constituent people of the company and developers of the software.

Consider Elon Musk and Twitter. Given Elon's personal beliefs and how adamant he is to enact and enforce those beliefs, do you consider him a neutral influence on the privacy of Twitter as a product? There is no way to see him as a neutral influence; he has direct influence by his ideological stance on the software. As such, if you have enough distrust in him or his ideological stance, that can transfer to distrust in Twitter as software.

In fact, it's not even about whether I support the CEO or whether I think his stance is "right" or "wrong" as you imply. It's entirely about how the CEO sees his beliefs in relation to the company and product he's overseeing. I could entirely agree with the CEO and still consider their influence to be a detriment to the product if he puts his ideology ahead of pragmatism, for example.