EU law requires members to tax tampons and sanitary towels at 5% if that's not an EU issue, I don't know what is.
EU law requires members to tax basically everything at 5%. 5% is the minimum VAT level.
Tampons and sanitary towels aren't penalised by the EU - they just don't have an exemption from standard VAT rules. In many countries they get the same minimum 5% as other necessities like food.
The UK had a historic pre-EU legacy 0% rate for certain items (most non-luxury food and books, mainly), which the EU rules permitted to be retained for those items, but tampons were never part of that 0% rate. And lowering any item to less than 5% is not permitted.
Basically, UK women were getting a much better VAT deal than most of the rest of the EU. Their food was taxed at 0% and their tampons at 5%. In the rest of the EU both food and tampons would be 5% (or more). And food expenditure is much higher than tampon expenditure.
Like Maya Forstater, I'm very cynical about the "period poverty" thing. Scrapping the very-low VAT level on tampons will have no real effect - hence corporate and TRA enthusiasm for it as a "yay we're feminists!" signalling device. (Recall that 19-year-old Labour fool who's name I've mercifully forgotten "campaigning" on it).
She recently said something on twitter how all these things like "period poverty" and "hygiene poverty" are basically distraction devices to stop you looking at the fundamental issue - poverty.