The issue I have with the arguments against is that there's an assumption that you'd never want to leave your safe little space ship, or that help will always be hours away, so you cling to the wreck. You plan for an emergency and a disaster the best you can. Sometimes it's not practical, but that doesn't mean you just abandon the concept completely. You don't get a parachute on a plane because you really can't use one anyways. But you get flotation devices and life rafts, even though odds are if you crash in the ocean, you'll prolly die. Space vessels have the same idea behind them - though while they crash, they really don't "sink"... unless you count gas giants maybe...).
To be honest, a lot of the time you don't abandon your sea-going ship either, even if you have lifeboats. Most naval disaster scenarios envisage you getting into the water and staying in boats near the ship until the fire (for example) burns itself out.
Anyway, outline your scenarios for review.
Ultimately,if you want credible starship disasters, follow a basic FMEA list.
The systems that are there to go wrong are:
Structure/Hull/Armour
Power Plant
M-Drive/Onboard Gravity
J-Drive
Fuel Tanks
Electronics/Sensors
Computer
Communications
Air Processors
And your standard list of failure types are
Does the wrong thing
Doesn't Start on command
Doesn't Stop on command
Works too little
Works too much
Works too early
Works too late
Leak/Contamination/Unintended Product
Triggers problem in another system
Essentially, it's a 9 x 9 matrix to drop ideas into.
I offer up the following to start.
So, for example,
M-Drive/Onboard Gravity &
Doesn't Start on command is an easy one to see - the drive is dead. This shouldn't provoke evacuation though, unless you're literally at anchor orbit and are just popping to the highport for parts, or you find yourself unable to decellerate after turnover in an interplanetary jaunt (a much bigger deal).
M-Drive/Onboard Gravity &
Does the Wrong thing is either the gravetic drive sending you the wrong way (not the end of the world) or some sort of 'short' in the system.
M-Drive/Onboard Gravity &
Works Too Much could either be a 'dutchman' situation (although you'd think physically cutting power to a drive should salvage matters in time) or, if dealing with the AG onboard, a serious problem. We don't know enough about gravetic technology to know how the 2-3G well that provides the oomph is kept seperate from the 1G that allows you to pour tea. Getting them...err...mixed up? could result in a rapidly uninhabitable ship - especially for a warship with a 5-6G drive. We know the drive projects a 6G gravity well - what happens if that ends up
inside the ship?
M-Drive/Onboard Gravity &
Leak/Contamination is a classic of every engine system ever. There will almost certainly be coolants/hydroplastics/something that is inside the engine that you don't want to come out. Even if it's just heat. I can see this rapidly making the engine room/deck uninhabitable but it would need to be something serious to affect the entire ship.
etc, etc.