You are correct: that's pretty much exactly how Lyft started: "oh, this is just ridesharing [1]", it's "just trips to places the driver would go anyway", and for which "you can choose to give them a nominal amount" to cover gas, totally optional (though they'll rate you poorly).
They've since dropped the pretense but a lot of the trappings remain.
Edit: Don't mean to sound like I'm "hatin' on" Lyft, just amused at the dance they have to go through to fend off busybodies.
[1] a term they still use against protest from journalists, and TBH, reasonable people
Lyft certainly lets you take more that 2 drives per day, and certainly not just too and from work. Also, at least in some locales Lyft has gotten rid of the "donation" fiction as many local laws explicitly state that any type of payment counts as a ride-for-hire.
This is basically just a carpooling app, and is nowhere near a rival to Uber or Lyft.
They've since dropped the pretense but a lot of the trappings remain.
Edit: Don't mean to sound like I'm "hatin' on" Lyft, just amused at the dance they have to go through to fend off busybodies.
[1] a term they still use against protest from journalists, and TBH, reasonable people