Unless you think there should be no tax threshold for pensioners (why?) this simply tells you the State Pension is currently so small that it falls below the personal allowance - well into relative poverty level.
Pensioners with some income on top of their SP, bringing their income above the threshold, pay tax the same as everyone else. Many seem to think State Pension's tax exempt. It isn't.
As @Lollygaggle's just said and you already knew, fiscal drag will put a bigger tax burden on the least well-off, including pensioners.