Speedos with socks and shoes is such a strange combination to be wearing, I can't think of a scenario where someone could wear that.
Shoes: He may not have owned slide-on shoes. Americans are fond of flip flops and other sock-free slide-ons but other nationalities differ, perhaps especially for men. Some foot conditions (metatarsalgia, eg) make wearing non-supportive shoes very painful.
Speedo: Some of the “no shirt, no shoes, no service” establishments will insist on footwear but be more lenient on clothing.