Thanks for posting the video.
I'm no great driver, but I think I can drive crap pretty well and your car appears to be on par with what I'm used to driving.
I'm not sure if it's because I was set up to expect this to be a string of Whoopsies or what, but a lot of those with the red-suited driver I saw coming. The driver seems to think the car is better than it is and goes too deep before braking or makes too many abrupt inputs simultaneously.
For a front wheel drive and in those higher speed situations or low adhesion areas of the track, the driver can't saw at the wheel like that. That FWD car is being asked to turn and/or accelerate / decelerate at the same time too abruptly for the car's level of adhesion. The driver is clearly not familiar with where the crossover point is where the car gets light or things just let go. It looks like it gives warning to a driver sensitive to it, but doesn't look like the red suited driver is sensitive enough to it.
It just takes seat time. I see it as typical over-eager newbie driving and more or less what the series caters to. It'll take discipline to willingly back off from what the ENGINE is capable of and back it down a few notches then slowly ramp up the speed and flirt with the grey areas of control after being able to repeatedly execute several stints with no near-incidents.
That car looks like it behaves a bit like my mini does when it is being driven at high speeds (on an open track)-- To go fast it want's to skate in a 4-wheel drift even though it's a fwd car. What I hope you're learning is that you can't do that with all of that traffic around you. The cars around you have waaaay different handling characteristics and can "hook" and "carve" a turn whereas my mini (and it seems your car with its current setup) wants to take a turn like one spreads an arc of peanutbutter across a slice of bread.
My mantra is "drive the laps and race the gaps" when I'm either wanting to test my or the car's limits: If there's unavoidable traffic clusters, just drive around without seeking to advance position. Let the packs of cars go by. Hang on the back of them with nobody on the left or right or behind you, then you can play with keeping up at their speeds and seeing how/if you can negotiate the turns or sections of track at those speeds they are traveling. Stick at the back of the pack as long as you can and if another pack catches you, the more quickly and uneventfully you let them buy, the sooner you can get back to spirited driving. Sonoma is not very conducive to this because it's pretty jam-packed.
Maybe that driver isn't a newbie, and sorry if I'm mis-characterizing him. But again, thanks for posting the foibles and letting us armchair quarterback and toss out "WhatI'dDo's" for the greater good.