I must say I sympathize. We have a pretty stringent code review system where I work and people are always coming up with nitpicky type of things.
Whenever I get technical comments from people that seems to me like they put alot of thought into, I always approach them for a quick chat, ask some questions even if you don't have any. It's a great way to build relationships, especially if you're new. And you tend to find that in the end it's not really important that you guys agree, but that you guys understood each other's technical perspective. This is an opportunity for you to network with this particular engineer, you should take advantage of it.
I have to add my idea to the mix. It's called the Pixelator. It's a site where you can upload photos of people and it returns to you the same photo but with all the faces pixelated.