The NCAA needs a limit on foreign players in women's tennis. Why would you need more than two per team? When they forced colleges to provide equal opportunity to women in college sports, I'm pretty sure they meant American women or at least residents of the US.
If you want more American women to play tennis, make it worthwhile to spend the hours and money working on their game. There's got to be a scholarship available at the end.
There is no significant money made for schools by tennis. It is mostly by men's football or basketball. If you have to spend this money on women's tennis, at least make it American women.
I think the US provides more opportunities than any other country for foreign players to receive a tennis scholarship. At the end of the day, they may become citizens and their children may become Americans. Consider that many foreign professional tennis players reside or have homes here in the US. Consider that many of the top international junior players come here to the US for training. If foreign players are coming here at the junior and professional levels, I don't think the NCAA is going to stop them from coming here at the collegiate level.
The NCAA may like the benefit that it brings as it raises the competition level at Division 1 schools. Coaches are pressured to recruit and develop a competitive and winning team.
At the end of the day, if an American does have scholarship potential, because of the competition level they may have less options at a Division 1 school and may have to resort to a Division 2 or Division 3, or if they're smart they can get into one of the Ivy League schools.
For instance, Suzy Tan (sister of Stacy Tan-playing for Stanford, blue chip recruit, NCAA singles final runner-up) graduated in 2012 and was a 4-star recruit. It was unlikely that she could follow in her sister's footsteps and play at Stanford. Fortunately, she got her free ride at Dartmouth. I am sure there are many others that eventually get scholarships.