It's not supposed to. ASL is a language separate from American English. It's like saying "German doesn't follow the grammar of written English." It's not supposed to because it's a separate language. People who are native speakers of German have to learn the grammar for English if they want to become fluent in English as a second language. That's what ASL users do. They learn English grammar as a
second language.
It's not supposed to be. German isn't good English either. That's the same concept. German is good German but it's not good English.
That's one of the major sticking points of SEE. Who are "they" and what right to do "they" have to tamper with someone's language? I don't think American English speakers would quietly accept some "experts" from Mexico trying to "improve" our language to make it conform more closely to Spanish. That's not improving; that's tampering.
Again, who are "they" and who gave
them the right to change someone else's language? Doing "what's best for deaf people" is a paternalistic 19th Century viewpoint that many people resent. Suppose someone suggested "doing what's best for black people" whether or not they liked it? There would be rioting in the streets.
That's how some ASL Deaf feel about SEE. They feel that ASL was taken away from deaf children, and were taught only SEE for many years. That's why it's such a sensitive subject.
I also believe that no one should criticize another for the signs that they use.
The differences just need to be clearly understood so people can make educated choices. ASL is the native language of American Deaf, SEE is an invented manual mode of English, and PSE is an adaptation of ASL on a long continuum used to bridge two language groups (ASL signers and English speakers). (Those are just summary definitions.)