They say it's a response to the rise in freelancing, gigs, and online selling. It's been rising for awhile, but with the pandemic, many people have been turning to online freelancing to pay the bills. Mind you, freelancers already don't have benefits, and they pay extra taxes (since freelancers are "self-employed," they pay the portion that would normally be covered by the employer, once they reach a mere $400 a year).
This is not a change in the taxes due, but it does mean a lot of paperwork for people who may not actually owe taxes (because their expenses reduce that $600 to less than $400 profit). If you are selling used personal items, you may not have kept the original receipt.