Wel thats entirely your opinion. Yale has loads of students who do not know perfect english. There are international students as well. Is your point really about "proper English"? Really?
You're kind of right - my point isn't so much about proper English (whatever that is) as it is about clarity of expression. Essentially, I wonder if you would have a better chance of getting into Y Combinator if you had a good editor proofread your Y Combinator application and your website.