An individual could sit placidly in the sun gazing out on a field of flowers and arguably be causing taxpayers harm because they aren't exercising and otherwise bettering their physical health (or maybe the pollen is increasing their risk of an expensive lung cancer, who knows).
There is more of an argument against taxpayer funds for the NHS than anything to do with sugar drinks in that observation. It is inescapably arbitrary what unhealthy behaviours are being subsidised vs. taxed.
That's because your observation is absurd and not grounded in reality. The reality is that obesity rates are too high in the UK. Most of these people overconsume sugary foods and overly processed foods. This in turn puts stress on the NHS, which affects all tax-payers in the UK so it's not a `strictly personal impact'. Overconsumption of sugar leads to measurably worse health outcomes than sitting in a field breathing pollen. The tax is not arbitrary.
You have to prioritize the issues, you can’t tackle them all at once, and inability to address lower priority issues should not be used as an excuse to avoid addressing higher priority ones.
High consumption of sugar is a worse problem than sedentary habits. “You can’t outrun a bad diet.”
There is more of an argument against taxpayer funds for the NHS than anything to do with sugar drinks in that observation. It is inescapably arbitrary what unhealthy behaviours are being subsidised vs. taxed.