Except that unlike income tax it is aimed at those who are poorest, even those who don't earn enough to pay income tax

Not strictly true, the many thousands of builders, plumbers, electricians, car mechanics and even Accountants etc who earn up to £38k from their owned companies as salary/dividend also don't earn enough to pay income tax - and neither they nor their companies pay National Insurance on that income either. The VAT increase is also aimed at these people.