Sounds like they don't negotiate efficiently. "Please give me a raise" is not efficient negotiation, no matter how aggressively or often you say it.
You're injecting a whole lot of assumption on how these negotiations are happening.
"Please give me a raise" is not a negotiation. To negotiate properly you need a trump card, "please give me a raise" doesn't show one.
I deserve a raise because...3 reasons. I have accomplished xyz and want a raise.
In my younger years I said I wanted a raise of 20 percent immediately after telling my manager that I told a coworker "to go fuck himself" twice.