DEI is diversity, equity and inclusion. They are basically saying that the fires are so bad because they hired a bunch of women, black and gay people. If they had only hired MEN (TM) to the fire departements, they would have it under control by now!
They are saying that the fire department, city, and state leaders were focused more on diversity than on the responsibilities entrusted to them to prevent fires, and ensure adequate water supply in case of a major fire. Someone also said that their intentional exclusion of white men from firefighter candidacy pools led to their lack of manpower to effectively fight the fire.