I think this article is correct in the basis of their assertion, though "shook" might be hyperbolic. Tesla is very reactionary, and this response wouldn't be the first time they reacted to a competitor's offering (or even reacted to the Bolt EV specifically). People seem to forget or overlook that Tesla's entire Model 3 unveiling was targeting the Bolt EV (or what they thought the Bolt EV was at the time). I knew even in late 2016 early 2017 that it was a mistake for Tesla to promise a Model 3 that was as cheap as the Bolt EV, and it turned out I was right. The lowest MSRP Tesla should have ever listed for the Model 3 until this recent price drop was $39,900.
Regardless, though, this is Tesla's MO. They react and respond to anything they perceive as a potential threat. Sometimes it appears that they do so through surrogates, but other times, it is directly as a company. Besides the Model 3's unveiling targeting the Chevrolet Bolt EV, they've reacted to the Porsche Taycan's record around the Nürburgring, the Lucid Air's Laguna Seca record, the Lucid Air as a model in general, etc. Also, through their surrogates, they've very actively attacked the Electrify America Network, and as a company, Electrify America's build out has forced Tesla to rapidly expand their Superchargers in a way they wouldn't have otherwise.
And before anyone says that the Bolt EV or these other EVs aren't a threat to Tesla, the Bolt EV sells better than any other non-Tesla EV in the U.S. market. GM could flip a switch and sell 100,000 Bolt EVs a year in the United States. Porsche reported that the Tesla Model S was their number one conquest vehicle (i.e., more Tesla Model S owners than any other car owner purchased Taycans). The Bolt EV is a threat to Tesla because it goes against everything that Tesla stands for, and the Bolt EV is rolling proof that affordability (not flashiness and immature doodads) will sell more EVs. There's a cross section of affordability and capability, and the Bolt EV might, in fact, be closer to that than any of Tesla's current offerings.