[guest post by Mr. Cohen]
In the world of Orthodox Judaism, there is an almost-universally-accepted idea that there is a shidduch crisis, and another almost-universally-accepted idea that the shidduch crisis is caused [at least partially] by an oversupply of single Jewish girls
If there is an oversupply of single Jewish girls, then why do Orthodox Jews continue to accept single female converts to Judaism?
Every time another single giyoret converts to Judaism, this increases the oversupply of single Jewish girls, which increases the severity of the shidduch crisis.
When a giyoret get married, she takes a Jewish husband away from a Jewish girl who was born Jewish (unless she marries a gair).
Giyorets are often far more attractive than girls who were born Jewish (look up the definition of the word shiksappeal) and they convert to Judaism because they want to marry a Jewish man.
Some Jewish girls will NEVER get married because the Jewish man they were originally destined to marry was taken by a giyoret.
But this tragedy could be prevented [in some cases], if only Orthodox Jews would stop accepting single female converts to Judaism.
Last but not least, women who have already converted to Judaism should only be permitted to marry men who converted to Judaism.