Earlier quoted context omitted.
Yes and I’m compelled to rob a gas station because the government has compelled me to pay property taxes /s
This is typical for court cases. Even if a party may have little to do with what’s going on trial, if they’re a relevant party in any way they can get sucked in and be forced to give a deposition. It’s totally possible to “plead the 5th” here, but the rationale here is all the relevant facts to a case have to be brought to light in order to make an informed judgment.
To me this feels like that Meta is trying to simultaneously measure up the market by making their competitors give out business plans that, frankly, are none of Meta's business, while also tying up smaller companies they feel threatened by in legal battles, as to drain their resources and run them into the ground (or, just a more appealing position where Meta can buy them up). And the latter isn't really new - I mean, Amazon pretty much "fired" mid-level executives and "placed" them at various competitors with the sole task of driving down the valuation of the competitor for easier purchase.
Either way, this kind of abuse of the legal system is disgusting, and even if the subpoena has legitimate reasons, it places an unfair amount of responsibility on an otherwise uninvolved party. The federal government could compel your company to produce an employee who can jump over a 5m wall, that doesn't mean it's suddenly possible.