Everyone apparently knows that those are good things, so they don't count.
Is it? The role of lactic acid in yogurt is to hydrolyze milk proteins and turn them into solids, so you can eat it with a spoon.
These things exist on a spectrum: kefir has many of similar properties as yogurt but is more 'drinkable'.
To be fair, back when I used to make kefir it often came out quite firm to the point that I could lift it out of a bowl with a perforated laddle and eat it with a spoon. What seemed to make the difference was using non-homogenized milk rather than homogenized. Using unhomogenized milk from Jersey cows also seemed to do the trick but the result was a bit too fatty.