All companies are tech companies in this day and age, it's a meaningless classifier. But not all companies recieve most of thier money from advertising and selling personal information, which makes ad company relevant classifier.
I'm sure Warren Buffet will disagree with that generalization of all companies being tech companies, especially since he, the quintessential value investor, doesn't consider Berkshire Hathaway as one.
Neither would Carlos Slim. Not that it means anything but at different times, each was once adjudged the wealthiest in the world.
Calling a company a "tech company" speaks primarily to its competitive advantage in printing money, not the industry it is in.
Google is an ad company.
Facebook is an ad company.