Sadly the topic of lactose intolerance is rife with misinfo, biases, and dogwhistles, hence my rapid-fire questions in the previous comment. Most commercial yogurt products sold in grocery stores today are heavily laden with sugar and so mildly fermented that their probiotic quanlities are nearly nullified. Commercial unflavoured kefir is slightly better, but the overall probiotic effect is still questionable since we don't have affirmative answers on how much of the microbes can survive through our stomach acid, or how much of them can establish in our guts vs. heading straight for the exit like passengers on a roller coaster.
The majority of nutritional science seems full of bullshit to be honest. I remember how we laughed at the Atkins diet when it first appeared as well all knew so well that the science told us fat was bad. Now Keto diet seems to be gaining a lot of acceptance, and refined sugar is the real enemy. Refined sugar being bad for you seems to be one of the few things that is agreed on. Will that change in another 20 years?
As for the spelling of yoghurt there's no correct version honestly, they are all transliterations of the same Turkish word https://en.wikipedia.org/wiki/Yogurt#Etymology_and_spelling