I think its a bit of a terminology issue, mixed with a little bit of theory/concept. So, yes, all chords have a root note, and yes, when we sit down at the camp fire, yank out our acoustics and Bob says "Do ya know this one? No? Ok, well the first chord is A, the next is D..." we're pretty much talking about open chords, and the norm for those is that the LOWEST note (whatever note is on the thickest string) is the "root" note. Bob is also going to call this the "bass" note, and while bass notes are usually on the Low E or A string, there's nothing that says they can't be on the D string too, but, again, just staying in the straight, no-frill "regular guitar guy" world, we would expect the bass note to be both the lowest note of the chord, and the root of the chord.
When Bob is teaching you "Me & Bobby McGee" and wants to show you the little "bass runs" between chord changes, those runs are going to be on the low E or A string, and will probably start and/or finish on the root note of the chord.
"The root note is its bass note"... that's right, in Bob's campfire world of guitar. However, there are tons of chords, I believe it starts getting into inversions, where the lowest note of the chord is NOT the root note. So that's something that you can just be aware of. If you start learning about triads, you'll revisit the idea of root notes and inversions. But for now, just know that all chords have a root note, and there is no hard fast rule that a root note is a "bass note" that is on the Low E or A...
