While Lex could not see through the endless strategies that Dao Lords may employ, he could see through some surface level ploys - at least by Dao Lord standards. For him, as the host, in such an incredible setting and company, to be so blatantly challenged by some random guests was actually not so random.
Maybe they were genuinely upset about Wu Kong's actions, but this was also clearly a probe. All Lex could say was that either these Dao Lords were way smarter than him, or way too dumb. Why would they challenge him when he could so easily bring them to such an incredible place, while also hosting some entirely out of reach characters in the same party?
Either they saw through his real strength and wanted to reveal it, or they were too dumb to come to the conclusion that anyone who could do such a thing would clearly have to have sufficient power. Another option could also be that they just wanted to show off.
