Why was Caliban so heavily industrialized?

Question

Before the coming of the Emperor on the planet, what would become the homeworld of the Dark Angels was a beautiful planet covered with forests, with a medieval civilization (though they had primitive versions of power armors and bolters).

After the Emperor and Lion'El Jonson got reunited, Caliban was integrated into the Imperium. An intensive industrialization follows. According to Lexicanum,

Vast swathes of the planet were cleared. Mines were dug and huge manufactories were built to provide for the Legion and the Emperor's Crusade. Gone were the villages and towns and in their place vast structures called arcologies were built to house the population.

A significant part of the population disapproved of that transformation, and I think it is one of the main reasons of the Caliban Heresy.

I have always wondered about this industrialization. Was it ordered by the Emperor (or the imperial administration)? Or was it a decision from Lion'El Jonson?

One the one hand, I thought at first this was the destiny of every world falling into the Imperium during the Great Crusade to be transformed into a Armaggedon-like planet and to be heavily industrialized in order to participate to the war economy of the Great Crusade.

On the other worlds, we know that some of the Legions' Homeworlds weren't treated in the same way as Caliban:

1. Fenris (Space Wolves) and Chogoris (White Scars) were left in their "primitive" state. Maybe it is due to their Primarchs' personality.
2. Prospero seemed to have stayed in its Pre-Imperium state, a mecca for scholars and a safe place for psykers (until Nikaea of course).

Was the industrialization of Caliban a standard thing during the Great Crusade? Or did Lion'El Jonson's personality had an influence on his planet's destiny?

Answer 1

Lion'El always intended to develop the land more once the great beasts were destroyed.

The novel Descent of Angels is an excellent source for this topic.

The promise at the start of the great hunt to kill all beasts is that when this is completed they will be able to develop and farm the land more without fear of being attacked.

This promise is what lead the knights of lupus to oppose him. Lord Sartana explicitly points out that once the beasts are dead the Knightly orders will lose their purpose, which Zahareal considers prophetic.

Now in the novel the plan was stated more to be for farming land as opposed to industrialisation, but with the realisation that Caliban was not the only planet of humanity their goals likely changed.

I do not have an explicit reference to Lion'El giving the nod ahead towards industrialisation beyond farming but I wouldn't put it past him since his focus was then on the Great Crusade and as you mention, the worlds of other Primarchs were not industrialised against their wishes.