Ad-libitum feeding is not force feeding. Noone goes and shoves the food into mice. The food is just available.
Also, CR has extended lives in many species, including dogs (see https://avmajournals.avma.org/doi/abs/10.2460/javma.2002.220...), not just mice.
The dog study you link also highlights another issue with this kind of research: they focus on osteoarthritis, i.e. cartilege in joints being worn out over time, since that was the most common chronic disease. This occurred equally often in both groups, but time until first treatment for this condition was 25% longer in the CR group. That's exactly what you expect just from the 25% reduced body mass of CR fed dogs which they report, since reduced body mass puts less stress on the joints. No attempt is made to account for this, it is not even mentioned as a confounding variable.
Taken together with the fact that they don't observe any significant increase in maximum lifespan of the CR fed dogs, it's again very unclear whether this is anything more than confirming the well-established result that when you inevitably get a chronic disease, higher body mass means you get sick faster.
Also while comparison to animals can be useful as a starting point it is no proof that it works anything like that in humans.