I greet all!

I learn English using different ways, I read articles on English sites including.
I am readind an article on
https://reason.com/reasontv/2015/11/17/can-pot-save-this-colorado-town
about the city Walsenburg’s authorities, who hopes to solve the financial problems of the city through the project for growing cannabis.
I understood everything, except the following paragraph:

"A lot of our clients were immediately priced out of the buildings or the indoor operations that we built for them because they were telling us to take a few hundred thousand dollars and block out a perfectly good environment and then take out another few hundred thousand dollars and recreate it," says Trani. "It didn’t take long for us to realize that the only reason people were growing indoors was prohibition."

I realized this so:

Сlients of company were growers of cannabis. They are grown their products in specially equipped buildings, but then it became unprofitable because of the high cost. Customers offered the company money for dismantling of equipment and installation on a new place, where production will be cheaper. Previously, they were grown indoor because it is only legal way of growing (<em>or growing was banned at all, then they acted illegally?</em>).

The text says “buildings OR the indoor operations”. Whay OR? It is my understanding that there is a building and inside someone makes some operations.

If someone will have time to help to understand, thank you in advance.