The problem with threatening a president or leader of a nation is that you then bring additional resources in that would not have been brought in if you were attacking an individual or business. They may regret having done so. Now the Secret Service, FBI, DoD, etc can all be brought in and use their resources to find and fight this group.
A lot to unpack here. A speculative Forbes columnist making a bold but not unprecedented prediction, a probable nation state bad actor opening performing espionage. Its the speculation that bothers me not the information. Having worked in the career intelligence community, my sense is that most of this is leaked information in one form or another and we are likely to see this become more normal during election cycles than not. Keep that in mind, its not about the individual but politics as a whole have reached new lows. No one is or will be safe from such attacks as these things start at the top of the mountain and roll down hill.
Still people will revel in their short term glory only to find themselves on the short end of the stick, soon enough.