The fact is that postdoc positions such as those described in PhD Comics do still exist and are quite common, particularly in academia. Postdocs working for government labs or research centers (NASA, NIH, etc) generally have a more defined role as a postdoc and are more likely to be very productive. Postdocs in academia are much more variable. I have seen them be essentially “faculty lite” positions where the postdoc gets a lot of professional freedom and can get a lot of great, career-building things done, and I have seen them be glorified lab assistants. In that regard, PhD Comics is still pretty much right on with those strips.
The moral of the story, though is that your mileage may vary. Every once in a while there will be a strip that really annoys me as being completely opposite my own experience, but inevitably then there is one soon after that hits the nail on the head. Not every comic can resonate with every person.
Of course, if you really don’t like it, just stop reading it. It’s still a far, far better depiction of academic life than the abomination that is Big Bang Theory, but if you find the latter to be funnier, then by all means, stick to that.