There is no medical proof of cages causing erectile dysfunction. Mental health is another thing; however. Chastity causes lots of feelings and emotions that can certainly contribute to problems getting an erection. This is usually due to being self conscious or nervous after a long period of being locked up. Some men can become very nervous when in the presence of a strong and demanding female and that nervousness can lead to temporary erectile problems.
On the flip side, many couples who live with ED find that male chastity helps to overcome, manage and sexualize/fetishize their erectile dysfunction.