Speaking ahead of England's one-off one-dayer against Ireland, Morgan discussed the process by which Hales was removed from the squad.
"I spoke to the coach (Trevor Bayliss) at depth," Morgan said. "I spoke to all of our senior players - I actually called the meeting with the senior players to discuss moving forward, how it would affect the team, and the team culture.
"We've been working extremely hard over the last 18 months to try and build that team culture and established values that we could adhere to.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"But with this Alex has clearly demonstrated a lack of respect for these values, and there has been a complete breakdown of trust between the team and Alex. Out of that meeting, everybody agreed that the best decision was for Alex to be de-selected."
Hales was fined and suspended for his part in a nightclub altercation which also involved team mate Ben Stokes in 2017.
Morgan said the decision to remove Hales from the group had been reached after consulting with Joe Root, Moeen Ali, Stokes, Jos Buttler and Chris Woakes at the team’s training camp in Cardiff last weekend.
"We will need at least 15 men to win that World Cup," Morgan added.
"For whatever way Alex would have dealt with it, the other 14 people would have been dragged down and that would have been quite a weight taken forward, and that didn't outweigh his performance."
Morgan confirmed all-rounder Jofra Archer will make his much-anticipated England debut against Ireland, while Dawid Malan and wicketkeeper Ben Foakes will also feature for the first time.
(Reporting by Hardik Vyas in Bengaluru, editing by Pritha Sarkar)
