Melvin is a curmudgeon. A curmudgeon is a bad-tempered old person who hates everyone. Since Melvin is so rude and disagreeable to everyone around him you would expect the audience to hate him back, but we don't. That is one of the reasons why this movie is so great. Melvin is a terrible person, he insults women and minorities and homosexuals. He's even rude and dismissive to his own editor (the woman who makes sure he gets paid enormous amounts of money for his books, and the woman he insulted just before the scene you are asking about).
This is the interesting part about Melvin's personality. He hates everyone equally (even a dog that he throws down the garbage chute). People INSIDE the movie don't like Melvin because they interact with him one-on-one. The waiters think Melvin hates waiters, so they hate him back. The homosexuals think Melvin hates homosexuals, so they hate him back. However, the audience sees that Melvin hates everyone, but we don't hate him back. Instead we feel sorry for him. We see him as a man who is trapped in a sad cage of his own making, devoid of friends and meaningful relationships. Of course, there are two others who see through Melvin's tough exterior, Carol the waitress and Verdell the dog.
But now I'm rambling on and not answering your question. YES, Melvin is trying to insult women with that line. From the very beginning Melvin has very cutting insults for everyone, and the audience laughs at all of them because they're so typically...Melvin!
Other great insults...
Immigrants..."Where'd you learn to talk like that, some Panama city sailor wanna hump hump bar?"
Bartenders..."I could be in bed right now with a woman who, if you make her laugh, you got a life. Instead, I'm here with you. No offense, but a moron pushing the last legal drug."
Homosexuals (after Simon gets beat up)..."Don't worry, you'll be back on your knees in no time."