It could be a "whoops" moment and they feel that the instant revive may be needed and more valuable later. If not, it's going to be a slog from start to finish either way if you aren't able to easily carry others. I don't think there's any ill intent. Most of us at some point bit off more than we could chew and were the corpse.
I just try my best to get them through and hope they don't get self-conscious and hop out near the end as some do. All part of public matches, you never know what you're going to get.
I also try to get defensive revive if it pops up when I see someone struggling. I would rather keep reviving them and have them struggle through so they can feel like they helped instead of leaving them on the ground.