Whatever the IT policy is is not really relevant. There is a big difference between ending or not providing support for older browsers (passively), and actively deciding to limit functionality solely on the basis of having an outdated browser.

Maybe the new search page uses features only found in the newest browsers. But since we have little details to go on (apart from the employee's canned response of "we are constantly updating functionality"), I'm skeptical that in fact they did this just for the sake of doing it "for the users' own good". That is wrong, imho