The problem is that the end user who has an ad blocker installed doesn't see a big "THIS FEATURE OF THE WEB SITE IS BROKEN BECAUSE YOU HAVE AN AD BLOCKER INSTALLED" message when things don't work. They just see things not work. Maybe a few of the more tech-savvy users will guess that their ad blocker caused the problem, but most users will just assume that your site is crappy.

If your site is monetized through something other than ads (e.g. purchases), it might be in your financial interest to make sure that your site works correctly even in the presence of a poorly-written ad blocker. Of course this depends on how many of your users are affected by the problem.

Now if your site is free, with no ads, then I can see how your philosophy could make sense.