That's the companies view point. You're selling them something and
they want the biggest bang for the buck.
You want the biggest buck for the bang.
Most sums paid in this industry aren't based on working skills, but on negotiation skills.
If there are loopholes in the negotiation that enable some of the parties to make false claims to increase their chances, they will use them.
A negotiation tactic: getting an actual job offer in hand for your salary + X, and then indicating to your manager that you have an offer for $S+X and that you would like to stay where you are if they could match.
Lying: not getting a job offer, but tell your manager you did.
Also lying: getting a job offer for $S, or $S+0.1X, but telling your manager you got an offer for $S+X.
"Lies" and "negotiation tactics" are overlapping sets.
There are negotiation tactics that are not lies, and lies that are not negotiation tactics, but just as surely, there are lies that are negotiation tactics.
> Lying: not getting a job offer, but tell your manager you did.
Sure, that's a lie. And if you tell your manager this as part of a stratagem to get a better compensation deal in your current job, its also a negotiation strategy.
It may be an unethical negotiation strategy, but it is certainly a negotiation strategy.