are you sure? it say "Generally, a person who in the course of a trade or business makes a payment of $600 or more in a taxable year"
trade or business is assimilable to mining in my view, or they ar enot very clear here
This is a normal requirement for reporting, even outside of Bitcoin. See
https://www.irs.gov/Businesses/Small-Businesses-&-Self-Employed/Reporting-Payments-to-Independent-Contractors.
For example, if you did some work for me as an independent contractor and I paid you more than $600 in a tax year, I have to send you a 1099-MISC. If I run a payment network business, and I make payments out to individuals, then I have to send them a 1099-MISC if they receive more than $600 per year. This could well be applied to mining pools, in that they ought to be sending their individual contributors 1099s.
So it doesn't really apply to individuals (except they might receive a 1099). In any case, it's for when you have paid out, not received income so there are no tax implications for the payer.