"Spell" is the name of the rule used by designers to give Rangers all necessary supernatural skills it should have. Maybe the name "spell" is bad because it goes back to a philosophical discussion like power source (arcane? divine? nature itself?) and because it gets compared to Wizard/Cleric/Druid (or any SPELL-caster).
But one could (and maybe even the rules should) describe the Ranger "Spell casting aboility" as more something less magic and, in that sense, more natural.
Let's take Hunter's Mark. It's a "spell" to make you do some decent damage - through "magic"... or, instead, you could just interpret it as a ranger's ability to go on a "hunter mode" in order to kill its foe, but that mode being so physically strenuous that he cound't possibly do it more than a few minutes a day... then some times a day after a few levels... then he'd be seasoned enough to do it pretty much every time (aka using 5th level spell slot).
I think most (if not all) Ranger spells could be interpreted as such, making no difference between a spell-less (or not) ranger.
Just to put a bit more lumber in the fire: we're just forgetting a stapple D&D Ranger that finds a lot of hate in this forums, but a lot of love from it's fans. Drizzt. Yeah, you knew it was comming.
He's:
1) Hunter Ranger, dual-scimitar wielder
2) Uses Hunter's Mark pretty much the way I described above... but have no clear spellcasting ability besides that of a normal drow
3) Arguably have an animal companion - say, you could have a figurine, your AC doesn't die just get banisehd, you can walk in the city without leaving it behind, bonus action to activate...
By the way... I don't get all the hate with Rangers spells. Back in 3rd Ed I disliked Rangers and Paladins casting, because it was cumbersome, took resources, and didn't do anything particularly great - and so I did enjoy spell-less variants. But 5es approach to spellcasting in those classes was, IMHO, very interesting.