What do you think of when you think of the penguin? I don't think of a
kernel. I think of the whole free software system which includes the kernel.
I think part of my problem is we have a revisionist past. It wasn't even
until later that I think an objection was made by RMS to the use of the word
Linux to describe the GNU + kernel system.
That said what I think of when I think of the penguin is not the kernel, but
that of a mascot which was adopted by the larger community and stuck as the
result of default. It was not a result of an official contest. That was won
by somebody else.
I did check out the wikipedia page and it does now (but didn't the last time
I looked) say "Linux kernel". It also says "official logo" and goes into how
it wasn't the official logo back in the day.