My shit view: At the root of this Islamic Studies + Arabic divide is that the secular academy has taken a theological category (“Islam”) and deracinated from its community(s) and then put it to use in a secular academic context as an anthropological and curricular category.

Salutary projects to define Islam as an anthropological category (w,out normative theology) have been tried, but those projects failed. Outsiders to the secular academy and students are understandably bemused, especially those who are Muslims with a trad view of Islamic education

“Islamic Studies” in a parochial context is theologically defined and vouchsafed by communities who see a tradition as something to be passed on and instilled. W/out Arabic, one cannot possibly acquire expertise in the Qurʾan, the ḥadīth, fiqh and uṣūl al-fiqh, kalām, etc.

While that’s not the sum total of Islam, it sure is a whole lot of it. But that’s not the project of most academics in the secular academy (non-secular academy is different). Islamic Studies must be expansive whatever it is: you get a seat at the table, but not the table itself.

What muddies the waters is that the secular academy has its own ideologues and ideological projects (you, me, everyone) and many aim to pursue brands of emancipatory politics and thus construct a vision of what Islam ought to be that infringes on the theological and, sometimes...

amplify marginal parts of communities that match that vision or even attempts to impose that vision on communities while leveraging their status and cultural capital as elites in higher education. Academic out/insiders sometimes cheer this, others chafe at it, some decry it.

Add to that scarcity: of positions of lesser to greater prestige, of time and funding, of students' attention, etc. and you get the internecine nastiness.
And it ain't ever gonna change. Still, the tension can be productive. So be civil and kind to each other, folks. fin