[OJFord]

I'm surprised it wasn't just "and all vowels" with the same reasoning, or at least 'a' (because I can more readily think of examples than for, say, 'e').

I suppose, though, there's an attraction in using b32 rather than b29... (Though I notice mid-word apostrophes are double-tap-selectable at least on macOS, so perhaps swapping 'a' for ''' would be advantageous, if more complicated to explain.)

[eridius]

The two "worst" swearwords that pop into mind both have "u" in them. Meanwhile, the swears with "a" in them seem to be the tamest of the lot.

[OJFord]

"Tameness" varies extraordinarily by region - an infamous example being 'twat' which throughout the UK ranges from friendly to vulgar.

Regardless of variance, I don't think I'd regard either the above or the name of a fat character in Austin Powers as "tamest of the lot".

[eridius]

I find it interesting that you're willing to say "twat" but not "bastard". I admit that I didn't think of either of those words, though I think they're still much tamer than the ones with "u" in them. Really what I was thinking of was "crap" and "damn".