Intellectual culture is necessary when guided by the spirit, but is harmful when devoid of divinity.
Illiteracy is also a problem, since some level of literacy is necessary to function in our modern world.
In truth, balance is the key. It is not enough to have intellectual knowledge. What matters is comprehension.
However, the point Samael Aun Weor was making is that there are spiritual initiates who have amazing attainments, but are not intellectual people. This is not to disregard intellectual cultivation. Instead, wisdom is the important thing.
For thirty years I sought God. But when I looked carefully I found that in reality God was the seeker and I the sought. -Bayazid al-Bastami