The support is time limited & it still prevents people from the community willing to help from doing so.
Given the effort of making captions is actually the work of writing the captions themselves the effort went from several hours of work to the same several hours of work +1 minute. Literally nothing of importance changed. And that +1 minute assumes Youtube's UX was best in class because of it wasn't then moving to a better UX could save more time.
The level of animosity toward anything Google does is absurd. If there was a captioning service making money and Google added captions they'd get shade for ruining a market. Now they are removing an arguably rarely used UI but still leaving the feature (captions) completely available. There's literally no harm. The people actually motivated to write captions will barely notice the change. They'll still write them. All they have to do is send them to the channel creator. If the channel creator doesn't want them nothing has changed. They had to approve them before, they have to approve them now except click 1-2 buttons to upload them. Sheesh
The process before was straightforward: a community member would author captions and submit them to the producer, the producer would choose whether to approve them right there on YouTube's site; the new workflow involves email, forms, files, and community members who are motivated to go out of their way to figure out how to create and communicate YouTube-compatible captions that will now be less likely to be published even if they are high quality.