He's either hilarious, lovable, and part of the charm and soul of the series, or just plain annoying to the point of being The Load at times, especially in the sequels where his annoying tendencies are flanderized. To be fair, Shrek is also rendered helpless against the guard, but he at least gets some good hits in, which they could've easily let Fiona do.
This is reflected in the evolution of the franchise's toyline: the first movie had a line of highly detailed collectibles by McFarlane Toys note yes, by Todd Mc Farlane of Spawn fame that could be appreciated by both kids and adults (just like the movie), while the toylines for the sequels (by Hasbro and MGA) were far cheaper and more gimmicky, and no longer targeted the Periphery Demographic of action figure collectors.
This caused the series to eventually gain a reputation of being "for kids", just like what happened to the Flintstones and Muppets. However, as time went on and Shrek became a Cash Cow Franchise, marketing for the movies became more kid-focused even as the content of the movies was only slightly toned down.
Fiona's actually more upset that her rescuer was an ogre, and she gets over that fairly quickly in one night after hearing Shrek lamenting that no one ever gets a chance to know him. We see she's fairly adjusted, despite the fact that Shrek points out how many knights were burned alive while trying to rescue her, and unlike Shrek, they didn't try to approach her tower first. Angst? What Angst?: Fiona has been locked in the tower since she was a child, because according to her a witch cursed her, and only a hero willing to rescue her could give her a kiss of true love.Alternative Joke Interpretation: It's arguable if Farquaad was "compensating" for his height or the size of his penis.And his men only attacked Fiona in retaliation. Alternative Character Interpretation: Sure, Monsieur Hood definitely seemed like a French Jerk, but keep in mind he didn't know Shrek was a good guy.So much was added to this little story that about the only thing it and the movies have in common is.a grumpy ogre named Shrek, a donkey (who is quickly forgotten about), a brief obstacle of a dragon, and a princess. Adaptation Displacement: You probably won't find a lot of people who have even heard of Shrek! by William Steig (and if they did, it's likely they first heard of it by watching the credits of a Shrek film).