Yes of course it's personal choice but if the covering is about modesty then why wasn't the man swathed too.
You do see all sorts of extremes like that couple, but the thing is, under whatever level of shoulder to ankle cover, Mrs. droopypants may well have been dressed in equivalent clothing. Perhaps that she is covered in public truly does reflect her choice, perhaps not. But if you pay attention, there are many modestly dressed Muslim men. The thing is, they blend in with all the other men in the UK who never wear shorts and regularly cover their arms with anything from a dress shirt and suit jacket to a hoodie. It is unremarkable. The majority of women i see with various levels of hair and shoulder covering, if their is an adult male with them, he is dressed roughly equivalent modesty-wise, including a cap (like a kippur) in many cases.
When getting up in arms, keep in mind, western women's own ability to dress however we want is pretty recent, and we still have to defend it against slut-shaming. Until 50 years ago, between puberty and widowhood, there were all sorts of dress requirements for 'decent' women, and women might be labelled, shunned, even arrested for exposing various bits under various circumstances, or because of their choice of undergarment. Trouserwearing was illegal, not just daring. In the Stonewall riots in the 1960s, some women in trousers were arrested under a law against women wearing men's clothing (also men arrested for wearing women's clothing).
From the end of the 1800s when public swimming became a thing, it was decades before swimsuits were 'immodest' enough to be practical. The arrest-able limits only gradually lifted from ankle to upper thigh and long sleeves to straps. The original bikini barely exposed two inches of midriff, but was shocking and shameful and something fathers and mothers proclaimed their daughter would not be allowed to wear! And every time the waistline dropped a bit more a new set of parents proclaimed, but now women old enough to have been those proclaiming mothers shave off their pubic hair as strippers used to do, in order to feel properly undressed in almost non-existent bathing suits.
When hats were still a social requirement 40 or 50 years ago. veils weren't uncommon, and being veiled for weddings or funerals wasn't just a fashion statement, some religious people took their meanings seriously. Some still do. The rules for clothing and veiling of widows and other close female family members began to be lifted with The Great War, there were just too many men to mourn is one explanation I have read. The following of these rules varied by social class, but whatever level was expected within your community and church, following it to safeguard your respectability, employability and remarriagability was crucial.
TODAY: Schools, both uniform requiring and not, have requirements for how short girls skirts can be, or short pants if they even allow them. Some schools disallow leggings as pants, but require tights under skirts. How much shoulder can be exposed by a sleeveless top, whether or not midriffs may be exposed at all, and what phrases and pictures on tshirts are acceptable. ETC ETC. I am not sure how long ago in the UK employers and universities imposed dress codes on females employees and students, but I know in the US some did until the 70s, and some few got away with it longer.
Someone asked why niqab wearing women get to wear black eyeliner, the answer is, that developed in the region for different reasons and it became so expected it is almost immodest not to kohl your eyes. But westerners do see it as sexy, because cosmetics were only worn by prostitutes until recent history, though really rich and/or older women could get away with varying amounts through the centuries. My grandfather cautioned his daughters 'a little powder, a little paint, makes a lady what she ain't'. It was a bit of a joke about covering spots or wrinkles, but also referred to not over doing it and looking slutty. Most parents still police their daughters use of cosmetics below a certain age or beyond a certain amount.