There was no time. Everything happened too quickly. Lex and the Tree were fighting, and the Tree was losing, but not fast enough. Lex decided to use a stronger technique to speed things up. Somehow, that had brought about an apocalyptic event that threatened to eradicate an entire continent.
If blame had to be assigned, Lex thoroughly allocated it on the Tree. Why was it fighting so hard? If it had just sat there and let Lex win, none of this would have happened. But a debate on why some people were just unreasonable was pointless, so it was best not to dwell on it.
Lex did not understand how techniques worked. Or at least, he did not understand why making them in certain ways within one's body brought about certain effects. Some people created techniques without understanding the why. As long as they could understand the effects, that's all that mattered. But such a mentality left room for unknown flaws, and so Lex did not subscribe to such a method.
