Maybe things look different today but those are some pretty good reasons for why it is the way it is today.
Most of the homophobic is used it's used to describe a situation where somebody isn't actually afraid of gay people.
I think it actually is a legitimate argument though that the feels of the entire gay population is more important than the reals of the very small amount of HIV infections that would realistically happen just because one number is so much larger than the other and HIV is far less consequential than it was when this policy was enacted. People tend to be bias towards avoiding extreme outcomes over causing a much lesser outcome far more often. See: nuclear being perceived as more dangerous than fossil fuels.
In any case there’s so many more important issues out there than blood donation among men who have sex with men the entire dispute smacks of bikeshedding. People are both discriminated against far worse, and are killed far more often, by different issues. It matters very little if people have the wrong opinion on this issue relative to if they have the wrong opinion on different issues.
That said, you are also barred from donating blood here if you have been in the UK for 26 weeks or longer from 1980 - 1996 (e.g. you lived there or you went on vacation there for a total time of 26 weeks or more).
Personally I understand from a medical perspective why this could be a concern and I dont think it is inherently meant to be homophobic
"You should not give blood if you have AIDS or have ever had a positive HIV test, or if you have done something that puts you at risk for becoming infected with HIV.
You are at risk for getting infected if you:
have used needles to take any drugs, steroids, or anything not prescribed by your doctor in the last 3 months
are a male who has had sexual contact with another male, in the last 3 months
have taken money, drugs or other payment for sex in the last 3 months
have had sexual contact in the past 3 months with anyone described above"
https://www.redcrossblood.org/donate-blood/how-to-donate/eli...
Yeah, but the policy doesn't include straight people, who are by now a higher-risk group. Which shows it's based on prejudice not safety.
I'd say a better policy would be excluding those who engage in nonmonogamous anal sex more generally, however I don't think the public has an appetite for that discussion.
Judging by the quick downvote I got, I'd consider you correct.
https://www.redcrossblood.org/donate-blood/how-to-donate/eli...