My first thought would be to laud the care and concern for women potentially being caused discomfort and even exclusion from women's spaces....
and ask how the speaker had supported the women being caused discomfort and exclusion from women's spaces all this time when men have been encouraged to use the space they find 'most comfortable' with utter disregard for the impact upon women.
I have to say, unless they were also equally concerned for the exclusion of any women, I would be rather cynical about the motives of the speaker. The same case for the frequently thrown around phrase 'butch lesbians' and great concern mentioned regarding them experiencing being challenged in women's spaces, when no concerns were raised regarding the lesbian groups being driven underground by men invading them, the attempts to make lesbians feel they needed to 'learn to cope' with straight sex in order to validate a man's gender expression without having any business wishing for more from a sexual experience than finding a way to 'cope' with providing the man with sexual access to their body..... <pause to shudder there> and publicly funded conferences to brainstorm ways for men to gain access to sex with non consenting lesbian women through the 'cotton ceiling' - literally how to get the knickers off non consenting lesbians to gain the desired use of their body. Unless the speaker was as concerned about those lesbians, I would be deeply cynical about the concern being displayed for these lesbians.
Because it would make the speaker look as though they had no concern for women at all but were merely adopting a pretense of it in the attempt to force men into women's spaces against women's consent and needs.
And then really it comes down to whether some women in the short term being challenged because of women's trust having been damaged by men in their spaces is worse than women being entirely excluded from any space by men being freely permitted into their spaces. And the point made by Sex Matters very early on about when you have chosen to look in a way that may, genuinely, cause another person confusion about your sex, you need yourself to take some responsibility for that.
Most women with trans identities, including beards, usually only have to smile and speak for another women to know their sex. And women tend to be considerably more sensitive to other women's needs and feelings than men are, hence many women with trans identities looking for alternatives themselves to women's spaces. And I personally am more than willing to reassure any woman who needs it without minding in the least, if this means that no women are excluded from women's single sex spaces and unable to access women's single sex resources. Once trust is resumed that these spaces are only for women and men cease to try and use them, the problem will go.
So the key thing really is: is this a genuine concern for women? Or is this a rather unpleasant use of some women in the attempt to force men upon all women?