I disagree. (chicken wings are bad form but so is shooting across your body)
Put it this way:
I am having a snap shootout around the left side of a dorito,tombstone, or totem. The guy I'm shooting at is leaning out leading with his right side. I have two options. Firstly, I could just use my right hand and lean out. I'll be exposing my left shoulder and arm (i play pump), chest, mask, then gun every time i snap out. The opponent will only have his gun, a sliver of his arm, and his mask out when he shoots (assuming he doesn't chicken wing). I'm at a disadvantage. My other option is to switch hands. Then I will have only my gun, a sliver of my left arm, and my mask out when I snap shoot. Now we are equal (assuming I've learned to shoot switch.).
This same problem becomes even more apparent when you play snake.
You are in snake 2 (at your 40 ish), another player from the other team is in snake 1 (their 20 ish). To shoot him out, you need to snap on your left side, whilst staying low enough to avoid his buddy across the field in the doritos. Try doing that without switching hands. It's possible, but you are gonna have to be many orders of magnitude better than him to even have a chance. Switching hands means you can shoot him out, then swap back and shoot across the field towards the doritos.
Yes you can play without switching. Yes you can get good without switching. However, if you play against the type of guys that I play against (D1-D4 tourney players with pumps or electros) you need every possible advantage you can get. Hell, if you just want to play better you need every possible advantage you can get. Learning to shoot switch is an advantage. It means you are more versatile as a player. If you can find some good tourney players who don't know how to shoot switch, please, let me know. But at least in LA, anyone who is decent (from the youth teams to the D1 guys) knows how to shoot switch. Against rentals, yeah, you can shoot lefty, or righty, or whatever, but any good oppenant will exploit your weakness.
Being ambidextrous when shooting is a huge advantage in competitive play. It's hard to learn, but like CP said, just play switch for a day. You'll thank me for it when playing the doritos or even the snake. Goodluck
At a rec play level, you'll have no problem winning gun fight as long as you are aggressive and get a good angle. Us pumpers don't enjoy getting shot out anymore than your normal player. Though we enjoy the extra challenge of playing, we wouldn't play if it was impossible to hold our own against equivalently skilled players. With a little skill and a lot of balls, you'll be slinging paint with the best of them (on the rec scene).