You can easily verify this wasn't the case by checking archive.is and seeing that the checkbox was removed for a day before the new one was added or checking stories and comments on what happened or looking at the commit history since the repository is open source.
If there were no facts in evidence, it your alternate possibility would still not be plausible since there's no reason the person wouldn't hide the checkbox if they didn't want to delete it but there's also no reason not to just delete it since removing it from the client is as much of a code change as changing the text.
If there were no facts in evidence, it your alternate possibility would still not be plausible since there's no reason the person wouldn't hide the checkbox if they didn't want to delete it but there's also no reason not to just delete it since removing it from the client is as much of a code change as changing the text.