I'm sure if the UK precisely defined what they mean by "fair share", and enforced their own laws regarding companies paying their "fair share", these companies would pay it. Or leave and do business elsewhere. Trying to do business without paying the legally required tax would be illegal, and immoral in your system, but not immoral in any system that views forms of income taxes as evil. (There are a lot of those around.)
There are indeed a lot of people who view income taxes as evil. Many, many people including a lot of people in the UK. But that doesn't stop them being thought of as a necessary evil, and avoidance as worse.
It's quite clear what the intent of the tax laws is, and it's quite clear that announcing a loss to the tax office but a massive profit to your investors is at the very least duplicitous.
tax is a robbery anyway. We only pay it because the government will take away our personal freedoms if they didn't receive payment. Do you honestly think if tax was 100% voluntary people would willingly donate without being coerced into doing it?