The reason Speedos are stigmatised

[Torchwatch]

In Alice in Wonderland Humpty Dumpty said that his words meant whatever he wanted them to. So it is with men's swimwear, all the manufacturers are using different words to mean the same things and the same words to use different things. There are differences in meaning between different designers and cultures within the English speaking world.

Although there was already a Bikini Atoll in the Pacific used for nuclear tests the swimwear bikini was introduced by French engineer Louis Réard and separately by fashion designer Jacques Heim in Paris in 1946.

British men's underwear has included briefs for many years and so swim briefs were just a variation.

You are therefore as right or wrong as you want to be.