for a little extra context, the chief of the commerce/merchant guild was a good "friend" of Rembrandt, they even competed for Rembrandt's wife (the one Makoto save from the curse like a 100 chapters ago), so the guy has a little grudge on him.
Makoto's business is going well and remembering that he's super naive and he pretty much let his people do the work without preparing well in the case of prices (he solds too cheap), like the potions that even got the church on him when they just got on the city, or the fruit that pretty much is only made on his land. Also stuff for the adventures, like weapons they just sell cheap stuff from dwarven blacksmiths (pretty much their wearker stuff is top class).
so when he finally meets the boss of the merchant guild he gets berated almost from the start of the meeting for preparing so bad to meet him (it took him too long) and then starts to mention how naive he is, how there's no formal route were he gets most of his stuff, so they clearly know he has a secret route (he teleports most of the stuff, but they don't know that, they think is a secret route without the dangers of the dangerous zone where he came), also gets reprimanded for selling stuff so cheap as he affects other people trying to sell their stuff (as I mentioned his potions are super good but too cheap), so when Makoto starts to feel bad, the guy goes harder on him and even mentions stuff like why hasn't he bribed anybody to keep his secret or to not get mad at him for selling too cheap (like giving money to his competitors because he's trashing them with his good quality and cheaper prices), then when Makoto starts to feel mad, he goes and told him even if he threatens him the only thing that he will do is going to lose any chance to work there and worst of all is gonna make Rembrandt look bad. At this moment is pretty much the second time that Makoto feels so dark and pressured by what was happening (like when he killed the adventurer that made a mess with the exploding rings on his land), as an extra at the time he was just chilling with his people and the same as here, he was engrossed on his new magic, the mana armor, so that meeting was like a brutal cold shower. The anime shown the moment, but I remember at the time with the WN, Makoto felt like he wanted to cry pretty much that guy trashed him, he didn't gave him a single chance to rebuke or something to go positive. The meeting pretty much ended with the guild master saying that he MUST gave his secret route and pay for the problems he made for the other people, pretty much destroying any chance of profiting on his company, he also (and this is something that I'm not 100% sure) mentions he knows he has demi human working for him and that he could blab him to the church to get even more problems.
then when he comes back to his people, Mio was pretty much ready to destroy all merchants starting from the guy, Tomoe wasn't a fan either, but at least the anime did it well there, Mio was visible upset even crying because Makoto was just being nice for selling so cheap, which is good as pretty much we have already seen, the society there is trash and the nobility just don't give an F about the common people, so Makoto thanks to seeing Mio like that calms down and just choses to say yeah, f*ck this place, after the School matches he will stop being a teacher there and they will take the company elsewhere, thinking about making a little problem for Rembrandt that helped him get the job and the plot of land, but they were pretty much firm on their decision to move. At the time they also finally got the information thanks to the library girl that the fortress that the heroes lost again the Demons last time, was the homeland of his family, so besides leaving that place they will start preparing to visit that place and talk with the demons to sell his stuff with them. (yes, at this point in time, Makoto was pretty much ready to switch sides and make business with the demons)
almost forgot, this event plus the one that happens right next to this, makes Makoto just don't care anymore about Hyumans for a long ass time (like 2 or 3 more arcs), like he just doesn't care anymore about the world of the trash goddess, like srsly, he cares about Rembrandt as a friend and a little from that look alike girl from the wastelands, but besides that, he reaches a 0 f*cks to give, even for his student which is something that Shiki gets frightened as he's the only one with a link to the hyumans of his servants, Tomoe and Mio don't care about that change in Makoto.
