I had a lot of time at work to think about why what Winslow does bugs me enough that I'm not entirely willing to side against May here.
1. His mobility is...almost an afterthought. There are times where the comics make small jokes that are a little off topic, and that may be it. I'm pretty sure this isn't a 'common' issue for him. If it is, then my heart goes out to him, and yes, at the very least he deserves something besides an Ipod for a body. Strange that Apple would make something so clunky. User friendly out-of-box is typically their motife.... But the major thing is that he wants to be like May, Momo, and Bubbles. His relationship to Momo and Pintsize is they were peers, and now at least one of them has basically evolved past him, and has seemingly ceased having an active relationship. He wants to feel equal to them. Pintsize is...well Pintsize. But basically Winslow has defined himself by Hanners, who while she appreciates him, doesn't really need him, just like how Martin doesn't 'need' Pintsize anymore. The dynamic has changed, and probably left Winslow with an identity crisis he isn't talking about.
Also does Hanners not have a skype that Winslow can call when he's left like this? Poor little guy.
2. I've said he doesn't 'need' because this is the very first time he's brought this up. I really don't think this was a burning desire so much as an impulsive "Hey, I want that too" which is easy to read into from an outside perspective. This isn't a "My life is horrible, I need this chassis to function" sounding decision. This is a "I'm feeling left behind, maybe a body will fix that" and it turns out no, it's not a quick fix for his self esteem.
3. His wording is pretty key for dealing with Momo. With Momo he's all "I have a new body. Dot. Dot. Dot." As if he's either expecting Momo to bask in this, or even say more. He wanted someone we've already confirmed isn't that close to him to drop what they're doing and make the moment all about him, and well, people have their own life. She already gave her kudos, and then he kept wanting to suck her further into his own ego an that is a major turn off. So that's the first strike against him.
4. "I decided I wanted to be a humanoid like you," those two words are probably what put the handbrake on the conversation for May. First, he didn't get the chassis like them. Momo got it at great cost to her friend, and has been working hard ever since, so May even might be offended on her behalf. But more so, May is saddled with this issued chassis. Whatever you think about her deserving it or not, it isn't the same. Winslow acts like this makes them equals, and it doesn't. The bigger word "Decided", as if this is just a whim. Yes, it means a lot to him now, but it didn't before. This isn't something we've seen him struggle with, and have a burning desire for, and with a goal in life involved. Just "I want what they have, because I don't have it. And I'm inconvenienced sometimes.". Strike two. I'm VERY annoyed with him.
5. I have my own baggage; When I came out, I was VERY young. Like at least 13. I went from feeling isolated and lonely because I had nothing to share to "HI I'M GAY!" to everyone I met, to the point where I was defining my as being gay, without there being any real meaning to it besides "Hey look at me, I have this special thing!" and that started being very alienating to people, and it took a similar chewing out for me to realize that if I wanted friends, I needed to identify as more as an actual person, not an orientation that I didn't even really understand the culture and strife involved with it. So that's three strikes.
So by the time May has her blow up, I'm feeling on her side in a bit. And I know its unfair. Winslow is not a bad person. But a good person can still be quite aggravating.