I know many people like that manner of listing (so you aren't crazy), but let me make the case for the other method. Often I'm looking up a spell by name, but I can't recall (or never knew) the level of the spell. Needing to look through multiple leveled lists to find where the spell (of which I know the name but not level) is, is frustrating. It's much more convenient to be able to just look it up in alphabetical order.
I assume the desire for listing by level comes from character building, where you want to know which spells are available to you. (In that case, you're in luck because Level Up lists that right there for each class).
I find the former situation to come up way more often for me than the latter situation. Even as a player looking up a spell my character knows (and the level of which I know) by paging through a list, it is faster to just look it up alphabetically then to have to first look up the level and then look it up alphabetically within the level.