The first of those instances is perfectly LG. Your option was to desert the helpless NPCs, to help your fellow PCs, and you most creditably resisted any temptation you might have felt to do it. No paladin could have done better.

The second is much less clear cut. Did you 'maintain cover' in order to deliver sneak attacks, or to preserve your own HP? And what does "pointedly made no effort" to save the idiots mean?

In answer to the thread title - I see nothing out-of-alignment in not going out of your way to help people who wilfully and needlessly choose to endanger themselves. Having said that, if I were in your shoes, I probably would do my best to help them without going out of my way. That is to say, if any possible mode of helping them has a reasonable chance of success and not too much risk, I'd take it.