The threat of imprisonment if you don't pay the fine is the polar opposite of anything "symbolic". It puts individuals at significant personal risk should they ever make the mistake of traveling through the UK, in turn limiting their freedom of movement permanently even without being in prison.
This is just not that big a deal for people who don't have family or business connections there already. It'll be like 'oh no, banned from a once-great place.' Had the UK remained in the EU, they might have been able to get other countries to honor such an arrest warrant, but as it is they just look petulant.
Sorry, being in effect banned from a country (and possibly anyone it has an active extradition agreement with, which is unrelated to EU membership) is a big deal.
Imagine being a US citizen, and suddenly being banned from Texas and Utah. It's not like you were planning on visiting those, right? Just remember to never accidentally take interstate 10, 15, 20, 40, 70 or 80 when driving around, that can't be too hard.
Suggesting it is okay to have arbitrary freedoms taken away because "you wouldn't use it anyway" is a very slippery slope. Who needs privacy and free spech, not like you want to badmouth the eternal supreme leader anyway.
I am not suggesting it's OK to have arbitrary freedoms taken away. I am suggesting that Hiroyuki Nishimura probably does not give a shit about the UK's temper tantrum.
You wrote that the theft of freedom was "symbolic" and "just not a big deal".
It also very much seems like Nishimura gives a shit by virtue of the active effort he is putting into his legal defense, consuming both time and money.
