The Exchange, at least the high ups, won't starve as much as the other people THAT will lead to resentment. Also about bribes, who is talking about money? I am talking about giving people the means to bring down the Exchange that are keeping them starving. Anger is not always rational, look at the Galactic history Vid "Breaking the Mandolerian Blockade", there were food riots on Coruscant. Or in our world, there are many occasions where staving people have overthrown a government, desperate people do desperate things, particularly when they have access to weapons.
So your argument here is that the people of Nar Shaddaa will hate the Exchange because Zann is making them starve? It's the other way around.
Firstly, "the people" have been oppressed forever on Nar Shaddaa. That isn't going to change anytime soon. Nar Shaddaa is cut into neat little corners where gangs control the people in their territory. You think they haven't put down rebellions before? I assure you that "people" are very bad off now and if they were going to roit, they would have. They already are starving. If the blockade made them worse off, they would be more likely to join organizations like the Exchange to fight it off.
Secondly, the people that matter, aka bounty hunters and smugglers and gang leaders, will not like Zann or the blockade. They'll hate how it takes away their power and ability to trade and expand around the galaxy. I encourage you to take another look at that "Breaking the Mandalorian Blockade" video. Who did the smugglers defeat? The Mandalorians, the ones behind the blockade. Why? Because it brought them profit and fame. They didn't help take the Republic down. Because blockades are bad for business.
And lastly, even if Zann's blockade manages to survive, remember this is the Smuggler's Moon. You know, like people who run blockades for a living? Zann's "food blockade" would not be able to stand up to thousands of smugglers doing what they do best: smuggling.
In short, Nar Shaddaa is already starving. Putting a blockade in place won't stop smugglers, and will only anger every single person on Nar Shaddaa against Zann.