Forced to do UML Class Diagrams before the code

Recently I've landed this new job at a great company where I got hired as a Junior C++ SWE. Since the beginning I've started noticing that something was not quite right, I started seeing UML class diagrams coming up everywhere and later found out that doing UML class diagram is part of the process (especially in the team I work in, you can't write code without defining the UML first). Specifically UML is used everytime BEFORE implementing a new feature, they require both class diagrams and sequence diagrams for a feature you have yet to implement. I don't want to hide that I passionately hate UML, be it in any form, I just consider it a complete waste of time and I believe it is useful only as a post-implementation representation of a feature (in case someone needs to grasp the big picture of what you've implemented). The idea to literally spend days working on a diagram that doesn't even solve the problem stresses me a bit and I'd like some external opinion on this.

Does your company use UML? if so, why the hell would one do it before the code?