I wish authors understood that "getting kicked out of the party" isn't just a scene for them to "get over with" as quickly as possible, but an interesting opportunity for world-building and getting to know the character. Like, what do we know about the MC? He apparently doesn't know when people are being polite to him but don't actually like him, since he was convinced that they were all good friends. He apparently doesn't have much of a spine, since he thinks it's ok for him to be kicked out of the party without keeping a reasonable portion of the equipment. The hero even says "it's ours", meaning it belongs to the party which he was a part of. So when he is kicked out he should get his share back out as well, since he obviously wasn't getting regular pay but instead the funds of the party were pooled and covered everyone's needs.
I find it pretty pathetic that he reasoned "my purpose in life was to defeat the demon king, but now I can't". I'm sorry, what exactly is stopping him from continuing his journey to defeat the demon king? I mean, the danger the demon king represents is still there, right? If he was motivated by revenge, or to protect his family, or riches, none of those are taken from him just because he got kicked out. This was the thing you worked your whole life for, wasn't it? Can't you form a new party, and continue with what was your life's purpose? No wonder everyone else kicked you out if you have so little motivation that the moment you run into a slight complication, you crumple immediately and give up. I mean, it's not even clear if he did it because he wanted to, or if he joined the hero when they set out (maybe they were childhood friends, something that would have been nice if the author filled in) and never thought of doing something else. If anything, the scene shows this guy absolutely had no business being in that party, he doesn't actually care about defeating the demon king, he was just along for the ride.
And apparently "the hero party" wasn't composed of adventurers? Where they getting paid by the goverment or the temple or something like that? He treats being an adventurer as a life of freedom or whatever, but wasn't that what he was doing already?
In short, like in so many other poorly done scenes, I find myself rooting for the hero rather than the MC. Sure, the hero and the others felt kind of like dicks, but we don't really know what the relationship was really like since the only insight we get is that of an unreliable narrator. "They were nice until they kicked me out" makes them sound bad, but maybe the truth was that they had been dropping hints for months and he was just too dense to notice, so they had to have an intervention and make their intentions clear.