Sure you can - but you can't be charged criminally for it, which is what you said should be done to those wanting to form a "shadow cabinet". And you can only be sued for defaming people, not the government itself.
That aside, there's also the issue of who determines what a lie actually is, and that's where the damn war is. Remember what they did during Covid? Who determined what was a "lie" back then? What did they do to people who "lied" about Covid, or "destroyed trust" in the government? Yet that's the exact road you want to go down. actually worse, because you want to prosecute for "sedition" or "treason" those who disparage the government.
You, and people who think like you in terms of shutting down dissent, are the biggest threat to this country.
Do you think Obama and the Deep States Shadow government is a good thing in line with what you are stating?