Yes, you are quite right in your observation. If you could have looked closer you would have seen signs above the entrances marked “Ladies”, “Gents” and, in these days of political correctness, “???” for those of an uncertain disposition.
There are many supermarkets in the UK that cater for differences in gender, ethnicity and specie. This gives rise to phrases such as “a bull in a china shop” and indeed “the elephant in the room”.
Separation like this while shopping has many advantages of course. While men ponder over the latest tech-toys currently available, women can peruse at their leisure over the latest hair dyes on offer. Other shoppers with more than two legs, or even none at all, can snuffle or slither around the assortment of troughs filled with goodies such as horse manure (wonderful to roll in if you are canine, of course). Payment is effected these days by smart phone with a fingerprint, pawprint or bitemark as identity.
There are also suggestions that fruit and vegetables should also be given access to purchase goods, but any decision on this will probably be deferred now until after Brexit has been completed.