I've found that when debating/discussing some subjects, people have a tendency to post long-winded videos as evidence, often an hour or so long. They will often post more than just one video at the same time.
My own opinion is that this is simply a tactic intended to flood you with too much 'evidence' to be able to view in your own precious time. It sits in the same category as Gish-galloping, for me.
I think that if a video does contain a valid point or genuine evidence you should be able to isolate that part and give a timeframe reference for it.
My free time is very limited and I'd be pressed to watch more than 5 minutes of a video.
(I tried to add a third option to the question but can't see how to do it)
Is it reasonable to expect people to watch entire videos more than 10-15 minutes long?
I don't get a great deal of free time, for this reason there may be long periods between my posts.
Please don't expect me to respond with insults and memes, I don't have time for it.
Please don't expect me to respond to Gish-galloping, I don't have time for it.