This actually doesn't surprise me. Valve is getting greedy.
But; to be clear; by using these tools, to unlock the DLC without paying for it, you are cheating in the game. That's a mere fact; and not a moral judgement of anyone choosing to do so.
Personally, I don't judge anyone for doing so; and would use these tools myself if I thought a DLC were too predatory, expensive or otherwise unfair to not have it available.
That's not saying it's fair or right for Valve to do so; nor is it saying the VAC bans or account suspensions are deserved. If you get hit by this; you absolutely should pirate every title you already own/purchased via Steam right away, and pirate anything else you want in the future.
The only way to make them regret doing things like this is voting with your wallet; and asking others to do the same. Stop spending money on Valve. Once their earnings fall they'll be forced to hear people's concerns.