1. Gray is a neutral color.
2. Gray is a color that blends with most natural setttings.
3. Gray is depressing as hell and makes you want to get out of your tent and explore.
4. Gray is cheaper than anything but white.
5. Gray is the color decided upon by cottage industry tent makers so they get a break on price for (secretly) ordering as a group.
6. Gray is great for stealth camping so park rangers won't find you.
7. Gray is popular in the former Confederate states. (The South shall rise again!)
8. Gray is the color that best matches your ti mug.
9. Gray is the color that makes us want to ask, "Geeze Loiuse! why do so many of you make gray tents?"
10. And finally, gray is a color that makes us want to buy a avocado green (or purple, or da-glo orange) parka just for a fr!kk!n break!
Really, do you want to lay in an orange or yellow or red tent if you have a migraine, a hangover or, God forbid, giardiasis?