My mentor was laid off because my company wants to make more money?

We work in a mid level company. Our C level management threw us a huge Christmas party to celebrate the most profitable year our company has had. Then once the new year comes along, they blindsided everyone and laid off a ton of the software engineers and IT staff. My team are all software engineers who work on the product along with deploying the cloud infrastructure. My mentor who’s the software architect that initially built the product with 1 other architect, was part of the layoff. He helped me become a software engineer.

I notice going through our internal portal that no one on the business side of the house such as HR, marketing, accounting, finance, admin support, sales, etc. weren’t laid off. Management provided department one on ones to be transparent about why. They said it was to reo’org and be proactive on the 25-26 revenues goals the investors have for the company. They can’t outsource the software engineers for legal reasons dealing with the state and federal contracts. However they can and are outsourcing IT support staff. When talking to my mentor today, he’s been blasé and laughed about it. He showed me he’s already been conditionally offered a few roles from past colleagues and a ton of interviews before the weekend started.

I’m just trying to understand from a business standpoint why they laid off the people who build, deploy, and support the company product and didn’t touch a single person on the business side of the house?