Of course they’re going on the offense. These are not countersuits as if people are bringing charges against them; they are practicing “lawfare” to silence people speaking out against the fraud and not just Dominion, bottom line.
By saying “seeing their name dragged through the mud” means you are emotionally invested in defending them. As it stands, Dominion ought to be indignant that their products were used for fraud and should be involved in discovery related to same.
They aren't counter-suits because nobody has sued them (as far as I know).
The "lawfare" you describe is standard practice for anyone who anticipates filing a civil lawsuit and must be ready to demonstrate in a courtroom later that they had availed themselves of other legal remedies before filing the suit. It's one of the basic principles of civil litigation in every state I've worked.