Yellow doesn't mean slow down. shyt means stop and if you cannot stop then proceed with caution. I assume you mean she slammed the breaks when she could have easily made the light, in which case yeah that's not just infuriating, it's bad driving.
Ngl, while driving through America I was utterly shocked at how people beat yellow, and red lights. Y'all just trying to endanger yourselves for no reason sometimes.
The thing that bugs me the most is when someone doesn't pull up far enough into an intersection to make a left so now I gotta wait a whole other light to make that left when I could have just gone in with them had they just pulled out enough.