Yeah that is strange, thats exactly what my bike sounds like, but mine eventually starts... However it takes forever when its cold.
I had a period where i thought something major was wrong, it was exactly like your video. So i bought new plugs, put them in and it started lol
I think the issue i had was i would put my plugs in, and right around the end they would feel tight, so i left them there, when in fact it was just a grimmy thread and i had to really twist them down to seat them all the way in. Initially i was off about a 1/4 turn or so but it made all the difference.
Try removing them, check the gap, clean them off and re seat, if not just buy new ones for 8$ gap those and tighten em down.
Its cheap but it might not be the carbs and this would save you a whole bunch of carb cleanings if it is the problem.
EDIT - also, try kicking it at full charge not the starter, maybe the starter is sucking voltage and giving you weak spark.