Because the implication of their argument is biological causation, which is pure conjecture on their part.

On the other hand, the entire posted article goes at length to study the social impact of social media for young people and young girls in particular and routinely references the heightened effect of the hyper focus on bodies for young girls.

Their comment is just a naked assertion. Would people find it offensive? Well, if the entire basis for your point is a strawman, then yes. But as far as I can tell, there is no causal evidence between femaleness and social media addiction or suicidal ideation. The need to leap to biological causation is unwarranted and unsupported.

Acting like they're already agrieved is a rhetorical slight of hand without substance.

There’s a great deal of evidence for innate sex differences in average social behavior, and those differences would readily explain the disparate impact.

It’s hardly fair to call that a “leap”, especially given the comparatively limited body of evidence in support of your preferred hypothesis.

"But as far as I can tell, there is no causal evidence between femaleness and social media addiction or suicidal ideation"

And yet the charts look wildly different.

If blue spheres and red spheres both explode, but blue spheres explode 25% more often. Would you hypothesise, discuss and test whether or not it might be it's essential blueness or would you prefer to avoid the most obvious difference and shy away from discussing it? Does that sound reasonable to you? If it is blueness, you will arrive at an answer much faster if you're allowed to investigate and talk about that. Perhaps then they can explode with the same frequency.

It is fairly common that biological causation is suggested or suspected when dealing with a difference in outcomes along gender lines. Sex hormones as an factor for behavior is usual one of the first suspect, especially if the difference is found around or after puberty. There are historically a huge number of studies done on testosterone to demonstrate this leap done by both researcher and public opinion.

That said, much of those studies where later found to be mostly wrong, and testosterone tend to be a bad predictor and a very weak influence on behavior. It seems more that hormones have a stronger influence on shaping culture than it has on shaping behavior.