also if you are below $600 per year as income from bitcoin, you don't need to declare anything
This is wrong. All gains need to be declared.
https://www.irs.gov/pub/irs-drop/n-14-21.pdf, unless this is changed now, read carefully
A-12: A payment made using virtual currency is subject to information reporting to the
same extent as any other payment made in property. For example, a person who in the
course of a trade or business makes a payment of fixed and determinable income using
virtual currency with a value of $600 or more to a U.S. non-exempt recipient in a taxable
year is required to report the payment to the IRS and to the payee. Examples of
payments of fixed and determinable income include rent, salaries, wages, premiums,
annuities, and compensation. Necessity to declare and actually owing taxes are two separate things. Please note the
"subject to information reporting" part. Although the section quoted has more to do with fixed payments.
I think you both are thinking of different versions of declared.