Ok, sure, fine, it was not technically demanding for a half sober lawyer to go over. Still why not on a Monday then, why not a 2 week horizon? Why do I have to give a reason, why do I have to skip dinner with my wife on Saturday, a plan I have had all week? If it's not formal, then why send it at all? Why send a 4th grade Valentine's day card? Etc.
Basically, it sent a message, at least to these guys. I think they read it correctly.
The challenge in equating our two experiences is the perspective from which the LOI was received. For them, it was a message in the form of another low blow from this high pressure accelerator trying to wrest away 50% of their business. With that mindset, a week probably would have been too short. Who knows.
Ours, on the other hand was, "Awesome! Troy called and invited us to the program! We finally get to quit our day jobs and go after this business full time like we have always dreamed about, and TS is facilitating that! Let's go over this LOI, which is simple and straightforward and doesn't legally bind us to do anything other than say we understand we are continuing the process and wont tell anyone publicly about it and gets us one step closer to Chicago and the success of our business!"
Looking through an LOI and getting it back to them was a joy for us, not a burden.
Without specifically being in the situation, it's hard to tell. The author implied that when they had spoken on the phone, he indicated to Troy that he wasn't sure if he was ready to commit, and then received the "please return by Monday" email within moments. It seems yours was more of a "yes, we're interested" followed shortly by the email. Maybe it's just their standard practice to immediately follow up "the call" with "the email," but I can see how it could be perceived differently depending on the receiver.
Basically, it sent a message, at least to these guys. I think they read it correctly.