To be honest (as you asked for), it does come off as egotistical and a bit condescending. I would remove the "Thank you and sorry" and "The bar is high because my word carries weight" sections. The tone of sentences like "I'm insanely lucky to be where I am today", and "My word carries weight" is a bit self-aggrandizing.

Without those sections I think the rest is fine. If you want to introduce the whole thing to explain why it's necessary I would entirely leave yourself out of it because it comes off as self aggrandizing. I would just write something like, "I appreciate your interest in working at Loom. I can't simply pass your resume on if you contact me, because it isn't fair to my hiring manager. It makes it easier for everyone when I provide the below information up front because its saves us both time".