Not taboo, mate. Whatever works for you is fine.
I'm a guitar and mandolin abuser myself, so a pick is almost like part of my hand, but never use one for 'ukulele. IMHO it limits the control you have over your tone, limits the techniques available (makes fingerpicking awkward) and, most importantly to me, ruins the lovely tactile experience of playing a uke.
Agree with the first part - do whatever works for you. No rules. It's your music.
Second - mmmm. Somewhat.
I use a pick sometimes. I'm also a former guitar player and for me it depends on the instrument, the sound and the music I'm playing. I use a pick with my steel-string, soild-body electric ukes about 99% of the time, and mostly play rock, blues and a little jazz on them. Just fits the sound and feel. Fingerpicking those slim steel strings doesn't make the sound I want.
On my acoustics, I use a pick - a regular, thin, plastic guitar pick - about 10-15% of the time. I don't feel a pick limits my control - I feel it gives better control for certain styles of music. But I don't use it a lot.
I tend to play fingerpicking songs - folk, or folk-style arrangements of vintage and pop music. A pick sounds a bit harsh for this stuff, at least to my ears. I belong to the fingertip school of play, too, not the fingernail school. I keep my nails cut to the quick, and use different parts of my fingers and hand for different sounds and different effects.
However, when I play along with backing tracks to do some blues solo practice, I often use a pick, even with an acoutic uke. And for a couple of pop pieces I used to strum aggressively on guitar, I find a pick gives me the sound I like. And with a pick, my other fingers act as a sort of counterweight when I'm strumming and I can open or close them depending on the speed and strength of the strum.
Anything with a slide sounds better to me with a pick, too. I like having a choice.
I don't like those big, fat and soft felt picks you sometimes get with ukes. To me they're like trying to string a uke with oven mitts on. I prefer a thin, light plastic pick. I can hold it at the end for strumming flexibilty or choke it at the tip for controlled lead picking. I also find hard picks a bit too rigid when strumming. But that's my taste.