Citation needed. The IRS can be among the most vicious of any federal agency. Having dealt with FATCA situations with overseas Americans, Treasury is, in my experience, nobody’s friend.
The IRS will generally take the most effective tack it can in getting the money it is owed. For honest mistakes, that usually means sending you a formal notice that it believes you are out of compliance and requesting that you pay them. If you pay them, all is forgiven. If you can show to their satisfaction, with supporting documentation, that you don't actually owe the money, all is forgiven. (I once got a notice that I owed $11K because of some stock sales I'd forgotten to report and education credits they didn't believe I was entitled to; after producing documentation on the cost basis of these sales, a course transcript from the educational institution, and an amended tax return, the total was reduced to $50, I enclosed a check for that, and I got a notice back that the matter was closed.) If you try to pull any funny business or argue with them and your arguments are not backed up in fact, they will viciously hound you until you pay the money that you owe.
If you pay them, they go away. Or sometimes they pay you and go away. (My first IRS letter was after my first semester of college, which was a bit disturbing since my whole income that previous year was ~$1k, but opening it revealed that I had neglected some sort of new education credit and they were giving me a small check to account for it.) My only remaining "fear" of the IRS is the scary Audit, because I know my record keeping is terrible and I don't want the anxiety of calling places and hunting down receipts or getting sworn letters from people that such-and-such checks were used for rent sharing not income/paying for services, and so I only hope that any audit could just be resolved by paying a lump sum even if with a bunch of effort that could get reduced...
I don't believe I've ever heard of someone being charged with perjury for signing an IRS document that wasn't true
You could look for some perjury charges if you disbelieve.
The IRS on the other hand with these kinds of notices is not out to get you, and I don't believe I've ever heard of someone being charged with perjury for signing an IRS document that wasn't true (and they genuinely thought it was true), especially from the perspective of a small time residential investor who is making an effort to be compliant with tax law.
I think a more sane proposition is this, if you only have a few thousand USD in crypto, you probably don't need to hire a tax lawyer or tax accountant (or both) to review your documents and compliance.
But if you're at 5 figures or above (10k USD+) then spending hundreds of dollars, up to a thousand or more, just to retain a lawyer and/or accountant could be a smart move for you to ensure that everything has been handled appropriately.
And it's not "hire a lawyer to review this one document", it's hire a lawyer and/or accountant to review your compliance with all tax laws and investment laws federal and local, and it's something you should do regardless of receiving a letter like this. If you have a lot of money in crypto and have never spoken with a lawyer or accountant about it, you should probably consider doing that sooner rather than later.
Even if you do "lie" to the IRS, and they think you have, they aren't going to have you charged for lying and put you in jail, they're just going audit you or determine you owe them money without you admitting it, then send you a bill and enforce that bill over time through wage garnishment, account levy, tax lien, etc. They would much rather tell you that you have debt and garnish your wages than lock you up.
Generally they save the courts for extremely egregious and offensive cases of intentional tax evasion (like people who use the 861 argument)