Presumably people who make less than $22,000 USD and have no capital gains, which definitionally cannot apply to anyone dealing with cryptocurrencies (as they're securities).
The long-term capital gains rate is 0% for single people whose income and short-term capital gains are under $40k per year, or married people under $80k.[0]
"People who pay no income tax" absolutely can apply to people using cryptocurrencies.
Every time I have a discussion about crypto on HN I want to go buy lots of crypto because there are clearly still some smart people that really don't get it, to the point of seeming deliberately obtuse.
Given that the median family income in the U.S. is almost 15% less than $80k[0], the majority of U.S. households don't have to worry about this problem.
You can try to make it out to sound really widespread if you want, but the facts don't support you.
And the fact that people with lower incomes stand to benefit more from crypto than people of higher means who already have access to reliable banking systems is part of the point.[1]