My man, they treated him as a gopher and tied him down with tons of menial tasks. Treating him as a servant rather than a team member. They actively TURNED him into a liability, and the Knight/Priestess very much did so intentionally. The Priestess was just more outspoken and blatant about it. The rest of the group went along with it or didn't care, which is just as bad. Sasha standing by and permitting it in itself makes her irredeemable.
Hyce BECAME a liability not by accident but by intent. He was never trained, never had any lessons, and they loaded him down with so many tasks he wouldn't even have time to train on his own. They also ensured he wouldn't get any experience nor fight the initial easy enemies so he'd fall back further and further. Sasha even fucking NOTICES this when they recruit new people, and do all these things with them. The same things that were done for her, while she received training Hyce was basically send to do chores and clean up for the party.
No, Sasha was a horrible, selfish, egotistic person long before that. She has a tendency to just ignore things that are inconvenient to her. To handwave them away. To ignore how others are treated and used, as long as the people doing it benefit her personally. She saw what her hanger ons did, and allowed it. She never even saw a problem with it and just went along with whatever bad excuse they gave her.
Hyce "understanding" is part of the author's endless glazing of Sasha. Something even the Japanese audiences is furious about and complains about endlessly. One of the most chill audiences who usually hardly ever speak up about anything. Sasha is a horrid person, in her own way she's more evil than many selfish and intentional evil parties kicking out people. And I doubt there'll be any comeuppance for the people who intentionally sabotaged Hyce this time around either.
Again. Hyce was desperate at that time to prove himself useful. He wasn't turned into a liability, he already was. Him doing all the 'menial' work was both a way to prove his usefulness to himself and a way to keep him from getting himself killed.
Not only that, but he was already trained not by Sasha (who had just as much experience as him) , but by his mentor the guild branch leader, the same mentor as Sasha. Hyce's problem was his lack of power. That was something only he could fix since it had to do with his special ability that no one* knew a damn thing about. Do not underestimate how powerful abilities can make a person. As far as we've seen in the story, you can't became an Adventurer withou the right ability to at least keep yourself or others alive.
*
well there were people who knew about it, but they were too high up and important to even meet. And they barely knew much more than most.
And again, the only one that actually sabotaged him was the priestess. The knight had conflicting feelings due to his feelings for Sasha, but in the end, he never actively did anything to hurt the MC. The most you can say for him is that his didn't back him up.
The mage and archer got along with Hyce. Mage and him were both book nerds. And he was the one that was mainly trying to research about MC's abilities but came up with nothing. But Like I said before, that guy is logical. He reluctantly agreed to kick him out of the party due to that logic. Though it was more of a neutral stance in general.
Archer straight up adores him like a big brother. She didn't even want to kick him out. But she was outvoted anyway. Hell, the manga didn't say it, but she was the one that actually tried to repair the relationship between Hyce and Sasha the most during the time before the series started. She never really gave up trying to get the team back together.
Chapter 6 and 7 of the WN let you know how the whole team felt about Hyce and expulsion. It is not as bad as you make it out to be.
Hyce's understanding isn't some Sasha glazing. It's reasonable.
Hyce understands that she kicked him out not because he was a burden but because the enemies they are facing now would have been too dangerous with his level of skill, he was going to die or someone would get seriously hurt or dead protecting him.
Hyce also understands that she was trying to help when she gave that info for a spot to help with his quest. She wasn't trying to kill him.
But Hyce also understands that she was pursuing "her" dream and not "their" dream when it came down to it.
She thought they had the same dream and they kind of did. But what they focused on was different. Sasha focused on the big picture, but Hyce was about the details. Results vs process. To Hyce, it's only "their" dream if they achieve it together. Since they didn't, it's her dream.
Hyce also understands that even though she didn't intentionally send him to the grave she also didn't appear before him after that incident, that when he was badly hurt, she didn't even try to clear things up. And the time she did try he was already strong.
Look. I'm not saying Sasha isn't at fault. But people over hate her for the wrong things. They focus on the expulsion but not on the reason Hyce had a problem with it. They focus on her sending him to the field but less on the events after. They think she's heartless, but in reality she just awkward.
She wanted to apologize, she wanted to explain everything, she just didn't know how. And that lack of social experience bit her in the ass.