Annoying how? Because he tries to tussle with defenders? Most defenders love players who try and tussle, especially ones like Hojlund who lose the vast majority of tussles. The only strikers that defenders don't want to tussle with are absolute tanks who know how to use their body like Drogba. As a defender it is more of a nightmare marking someone who you never know where they will be, someone who drops into areas you don't feel comfortable following them. When a defender is occupied, most of them like it because they're doing something tangible.
Hojlund does nothing to test defenders reactions or decision making, he doesn't play passes in behind players, he doesn't hold a defender off, touch to a team mate and spin off, he doesn't make good decoy runs to take them out of zone, he doesn't make the correct runs across defenders or across goal, he doesn't make darting runs one way then the other or keep them on their toes. He is very predictable and offers literally nothing in the air so that is comfortable to deal with whenever the ball goes long or high, he is never able to create that little gap to take a shot anywhere on the pitch. He is one of the easiest people to mark that I have seen, hence why he never gets a shot attempts and rarely scores.
These are all things decent strikers do, let alone a top striker, even the simple ability to receive the ball under pressure, keep it and lay it off would be mega useful, but when it goes up to Hojlund the majority of the time he ends up on the floor and he never knows how to evade CBs.