I think HMRC are playing with words. If you do something that reduces your taxes, because it reduces your taxes, it is tax avoidance.
The only reason I go through all the bother of opening and sustaining an ISA each year is because the interest is free of tax. Why on earth otherwise should I do it? I can and would save money much more easily without the ISA wrapper.
We had a Deed of Arrangement on my DF's will to transfer some of his estate directly to my DC, rather than through me. This meant that if I died within 7 years of his death there would be no inheritance tax due. In fact he died more than 7 years ago so the tax avoidance measure was unnecessary.
Tax avoidance is entirely legal. If tax accountants find ways of using it that didn't occur to Treasury Mandarins, well the Treasury should either, immediately close the loop hole or employ some of these tax accountants to stop the loopholes being there in the first place.