I assume by reflex laughs you mean you're laughing because the other guy is? I prefer to make my own laughter to (insert rude comment). Easy enough to search online for TV shows you might want to watch, assuming you're like me and don't have a $$$$ system with a schedule you can thumb through.
No, they're laughing. A short, uncontrolled shout of laughter either from stuff Ive seen in the past or new sketches or clips.
It's a cultural difference thing too.
It's nice that down to earth middle aged American guys, gals or couples from small towns, big towns or 'red necks from the back woods' start to get the old British comedy greats, or more recent long running shows / comedy panel games / televised stand up shows over the last 15 years in the UK.
Watching them get tickled hysterically and have to pause briefly and know they got that line or saw someone's facial reaction or gesture on TV, and want to see more of that show or person when it's over is great.
We (in the UK - I'm Irish originally) can have much cruder words and sexual innuendo or body function content that wouldn't fly on TV in the US, but for the most part it still has a touch of class about it when done with real talent and comic ability. Panel show comments and reactions on screen are mostly unscripted.
Yes, with You Tube reactors you can tell who are genuinely enjoying something and appreciating it, and those faking a choking laugh and just trying to get paying patrons or build subscribers so You Tube pays them a little. I haven't paid anyone, but would give a few bucks occasionally to some if I could. It's a lot of work for them with little equipment, and a lot of their uploads get taken down for one reason or another so less than half stays up.
I like these guys and gals. Three or four years ago I was like you, only much cuter apparently, and more handsome obviously.
I enjoy these few channels, with their average 10 - 20 minute uploads. I'll watch what I want to watch based on past clips of the same shows or comedians the reactors have watched before and want to see more. They often can do full 30 minute episodes too.