Well, Mubarak wants to rule the country and has ordered the police and army to disperse his opponents (using deadly force). Meanwhile they are attempting to call as many of the population onto the streets as possible and hold a general strike in an attempt to force him out.
State control over means of communication (state tv, ISP infrastructure) will prevent these calls from reaching the population quickly and helps stop the movement.
You are proposing to side-step the question of taking over tv stations/ISPs/telephone exchanges by building a second communications network alongside the existing one. This won't work for two reasons 1) people who are revolting because £50 a month wage minus £30 rent can't buy food will not have the necessary equipment, 2) The Egyptian government can use some of the $1.3bn military aid from the US to buy 2.4GHz radio detector vans to drive around and arrest regime opponents with their own network.
Classically in Barcelona and St. Petersburg the revolutionaries were able to take control of the telephone/telegraph exchange and prevent the state from organising itself effectively. The same logic applies today, just that the IP infrastructure that is also important in organising a revolution or its counter-revolution.