I donate about once a year. I expect exactly zero people to agree with me, but here goes.

Ignoring the moderation and your like or dislike if it, Robin still has to pay for the site.
How much time do you spend on Pinside? Is it weekly, daily, several times a day, several hours a day? I personally spend a lot of time on Pinside. I really enjoy it. For several years, it has been my primary website for fun and entertainment.

Looking at the post counts of many members, they seem to follow a similar usage. Rationalize all you want. If you use it nearly as much as I and don't donate, you're a cheapskate.