Superloud: in the daily mail article, there is no suggestion of rape - they just say there was sex. I know it could be daily mail being rubbish, but if it genuinely was consensual sex - would that be so bad? I may have watched a bit too much OITNB but I assume some sort of sex happens in any prison without trans people involved.
You ... do occasionally read feminist theory, yes?
There are those who doubt that PiV in patriarchy can be consensual. Now, agree with that or don't, but do you really think women who are imprisoned with violent males have a free choice?
Also consider that many of those women are already traumatized by male sexual violence. Some may have Stockholme Syndrome and cling to the first male who seems nice, as they hope he will protect them from the others.
Even men prostitute themselves in prison in exchange for protection ... and you think there is a free choice for women who are housed with males?
Yes, homosexual sex happens in prison. There is, however, a very important difference between homosexual and heterosexual sex. Mainly that the latter can lead to pregnancy, with all the risks involved.
Also, women in prison are unlikely to have been groomed for sexual abuse by women, therefore, the chance that lesbian sex in prison is consensual is way higher. (And I am sure it doesn't happen nearly as often as the TV wants to make you believe.)