Maybe his argument is that cerveza vaccines were not part of the deal when he joined, which reminds me of a joke that was circulating around army.mil circles a few years ago:
SGM for a brigade comes into the brigade commanders office and says, "Sir, I just put in my retirement papers. I want to tell you I've really enjoyed the last few years working with you. It capped a great 30 year career in the US Army."
BG says, "But Sergeant Major, I just put you in for CSM of the Division! You still have a great career ahead of you! If you play yours cards right, you could be SMA before you retire!"
SGM say, "Sir, I really appreciate your confidence in me. That means a lot to me, but when I joined the US Army, any small sign of homosexuality got you kicked out. When I was a junior NCO, it was "don't ask, don't tell". When I was a senior NCO, it was OK to be completely out of the closet. Now it's a prerequisite for promotion."
BG say, "That's true. Do you have a problem with that?"
SGM say, "No sir, but I just want to get out before it becomes mandatory!"