Money, probably. Netflix also does this, for unilingual shows as well. Maybe a personal curse for speaking 0.8(1+1+1) languages, but man. Whatever AI they cook up, the quality will deteriorate if this stupid policy stays. It still will even if the policy doesn't stay, but that's not the point.
If you have a fediverse account, you can quote this note from your own instance. Search https://bsky.brid.gy/convert/ap/at://did:plc:7kz5fuok6aeujssccwrbvroo/app.bsky.feed.post/3md5mskdoju2v on your instance and quote it. (Note that quoting is not supported in Mastodon.)