My bluntness is not due to me being mean or rude, but just me wanting to say my piece and resolve issues as fast as possible.

When people say this, it often comes down to the inability to listen to other's points of view. People believe they are right, want to "say their piece", and have it accepted as correct (masquerading as "resolving issues fast").

The first step to overcoming this is a bit of humility and acceptance that the opinions of others are just as valid.

I don't care. What needs to be said should be said

I don't have time to care about feelings.

Again, this is all part of believing that your opinion is right, other people are wrong, and being unwilling to listen to other's points of view.

You might want to look up active listening. People who practice active listening are in high demand in the workplace. People who engage in the workplace like you do above are rarely successful. They limit themselves. They create their own ceiling. They don't improve because they don't consider the viewpoints of others. People who are "always right" will always stay at the bottom because they are not trainable. You may be "blunt" to others but in the end, it is you who is most harmed by this.