You phrased this as an either-or thing, so I am actually genuinely curious....what exactly is wrong with this attitude?
We as people do a lot of things in our lives that probably don't make a difference, but that makes us feel better as individuals. Genuinely, what's the harm in cutting something out of your life because it makes you feel better?
Just look at this thread, several comments about "oh yeah that's what people without morals always say." As if whether someone spends $10 on an old book of Dilbert comics has far-reaching moral implications.
I always find it funny how these sorts of things always seem to roll one way. You can be supportive of him all you like, but if you're going to distance yourself, do it quietly - preferably silently - and please don't say anything that might cause anyone to feel bad about it.
I will admit that I haven't read Dilbert regularly since the early 00's, and certainly not since Adams revealed his uglier side - but that has more to do with me finding out about and preferring Achewood's Roast Beef as my comic surrogate computer nerd.