Most Techs verbalise freely when working.
The comments by the guy in the video would be normal day to day chatter in any real Electronics Workshop.
It's damn all to do with the "Youth of America"---Aussie Techs were like that in the 1960s!
The only reason it sounds excessive is it is on on a Youtube video.
The comments,particularly,the swearing,would be confined to the work area in most jobs,but if you are to "look over the Tech's shoulder",you get it "warts & all"!
At one time I developed more expertise in fixing Studio Picture Monitors than I had ever desired!
One delight was converging the things.
This had to be done "live"--- looking in a mirror & groping around in the "guts".
After doing our best with the variable controls,to get the convergence as close to perfect as possible,we inserted plastic "wands" with a ferrite or similar tip between the tube neck & deflection yoke & wiggled them around.
This,on some units brought the Tech's hands very close to,& sometimes
in contact with non-insulated terminals on that yoke.
It wasn't really dangerous,but it hurt,& I would often be heard saying something like,but not quite exactly,
"Massey-Ferguson!" when this occurred.
As for his work practices:-
They look pretty standard---some people are more fussy with flux use than others.
I use quite a lot,but I tend to clean up between applications.
Use of liquid flux will almost always create a good joint--many times the flux core in solder alone will not be sufficient for this.