Yes and I applaud him for that. Please go and read the Pinside FAQ concerning TILTs.
Just to be clear: TILTing is not a bad thing. It is there to help people (who choose to do so) to auto-hide stuff that could get them into problems, e.g. when viewing the forum at their workplace. The TILT system is what allows Pinside to have some pictures that would otherwise be unacceptable for a public forum.
In fact, you are expected to self-TILT your post if it contains NSFW content or images like the one you just posted.
This has nothing to do with being prude or wether or not people enjoy the image you posted. It's simply a common courtesy system, designed to give people a heads up: "hey this content posted here could be viewed by some as inappropriate/NSFW".
It's up to you to decide where to set your TILT threshold (in your forum settings screen):
Note that continued failure to self-TILT your NSFW posts could lead to a site ban. We expect everyone to cooperate with this sytem.
Lastly, if someone is TILTing your posts while they do not contain NSFW content, please notify a moderator. Abuse of the TILT system is a serious offense and most likely a cause to be banned form this site.
Hope that clarifies things.