Ramses wasn't forgiven; he choose not to. He continues to slay Moses's people. I do apologize that I didn't make it clear about which Pharaoh are we talking about, but I was referring to Ramses. Ramses is the Pharaoh of Egypt after Joseph. Egypt has forgotten about Joseph and came up with a crazy and sinister idea. When Egypt continues to slay the Hebrews for more than 500 years, enough is enough!
God came to Moses to tell to Pharaoh to let his people go. God was willingly to forgiven Pharaoh; however, NOOOO! I hope you get it.
I'm confused on the part you say that Ramses became the Pharaoh after Joseph. Lol
Joseph ain't Pharaoh. He's the Pharaoh's right hand man. The Pharaoh was still on top of the hierarchy and Joseph was granted a special privilege to rule anyone in the Pharaoh's political system.
When Joseph and his 12 brothers' seeds spread across Egypt, Miriam, Aaron, and Moses were born and so was Ramses. Seto wanted Ramses to follow his footstep killing off the Hebrew babies and enslave all the Hebrew elders until they die. God already knew both Seto and Ramses have stiff-hearts. There's no way to change these kind of people when their pride is too great.