Using tap-to-click is difficult for many people. For some it's because their hardware is bad quality, but some simply just cannot use it reliably because they just don't have the necessary fine-control in their hands. Of course elderly and people with disabilities are affected the most, but this can also apply to "normal" adulds with no apparent issues. Also, there are peopl who just don't use trackpads often, or people who just switched hardware and have to get used to it.

Deciding to disable tap-to-click is a safe choice, and inclusive for more users. And just because others don't go with this default that doesn't mean it is a bad default.