That seems like a pretty insane default. Do you happen to know what the thinking is? While I'm fortunate enough to have never needed to spend significant time working in JS and its spawn, I've heard a lot of good things from people I respect about TS and its incremental typing approach, so I'm starting from the baseline assumption that this is a reasonable choice.
There seem to have been a few options that are disabled by default and emit additional errors, that slowly get turned on by default in later versions. Perhaps this is one of them.