When I was growing up, my mom used to straighten my hair for me because that was the only way for it to look "nice." This was about curly hair not looking good, not about any Jewish stereotypes. My mom grew up in the 1950's and 1960's, when the only "nice" way to wear your hair was straight with a flip or supershort.
I didn't go curly until I was 16 because I was caught up in the idea that curly hair looked like you'd stuck your finger in a light socket. Funny, but after I went curly, my hair got compliments that it never got when straightened.
"There is such a thing as natural beauty, but every woman needs a little help to bring it out."