The part highlighted by you was just an optimistic supposition made at the time when the first article has been published. That supposition only expressed wishful thinking that was not based on any data.

The study on mice published in the second article has been made specifically to test this optimistic supposition and the results have shown that it had been false, i.e. the weight loss caused by semaglutide is different from the weight loss caused only by calorie restriction.

More studies are needed to elucidate whether this effect of semaglutide is really harmful or maybe it can be reversed or avoided by combining the medication with a better diet, e.g. with a higher protein intake.