Making spare parts for the B-52, or maintaining security fixes for Solaris (which has its fanatic fans) can be rewarding, no question. But to work on the Itanium any time in the last decade must have been soul-sucking.
In that time frame, it wasn't clear that horizontal scale out architecture (aka "the cloud") was going to dominate, and that scale up systems were going the way of the mainframe. The thinking was that there would always be a healthy balance of scale out vs scale up, and btw, HP alone did $30B+ revenue yearly on scale up with very slow decline, just like the mainframe market, which is still $10B+, even today.
To put that in today's terms, if you pitched a startup with a $30B TAM, VCs will definitely be returning your emails.
So no, it wasn't embarrassing to talk about working on IPF any moreso than it would be to talk about POWER today. It's just another CPU architecture with some interesting properties but ultimately failed in the market place. Just like Transmeta or Lisp Machines.
What should be embarrassing, but clearly is not, is to slag off entire industries not knowing shit about them.
Edit: I think working on B-52 parts would be an amazingly fun job.
Not everyone's identity is based on what they work on.
it comes from the people you are working with, and the people you are serving as customers, and whether these stakeholders are being treated well and having their needs met.
Intel and HP (where the people "supporting and incrementally enhancing" itanium hw & sw work) are very much Silicon Valley companies.