I think it becomes intuitive when you think about how sailing works (presuming you understand that…), you can sail just fine with side-on wind because you’ll just turn the sails on the diagonal and the wind will blow to your rear, and then you position the boat and rudder to largely turn that force into forward movement.

Same kinda thing will presumably happen when biking, except instead of boosting you it’s just making you have to push against the sideways wind as well as the regular wind resistence. Pretty sure i remember making tacking movements in sideways wind on a bike…