You still need capital. This could have been executed by some bored teenager who had nothing better to do on summer break (and likely has no access to capital or loans).
Time is also a factor here. It's possible the hackers here were afraid their insider would chicken out. If they were afraid of that, they don't have time to setup a realistic looking brokerage account, transfer money and do some trading to make it all look good. That type of setup would take weeks or even months. If you sign up and the first thing you do is go all in on TSLA puts shortly before this happened you're gonna be on a list of suspects.
Also, didn't most of these tweets happen after the US markets close or just before? If the market had overnight to digest what had happened before trading opened the next day, the markets wouldn't move on information that had already been determined to be false.
(This is assuming that the hackers did not have control of the time window in which they had elevated access.)
Time is also a factor here. It's possible the hackers here were afraid their insider would chicken out. If they were afraid of that, they don't have time to setup a realistic looking brokerage account, transfer money and do some trading to make it all look good. That type of setup would take weeks or even months. If you sign up and the first thing you do is go all in on TSLA puts shortly before this happened you're gonna be on a list of suspects.