You are confusing two separate issues.
One issue is whether an insurer can refuse to sell a policy to someone with a pre-existing condition.
The other issue is under what circumstances an insurer is legally entitled to refuse to continue to insure an existing customer.
Leftists often lump these sorts of disparate issues together in order to confuse people into supporting intrusive, unconstitutional government.
Please do not assist them in doing this.
Yes they are two separate issues. But they are both very similar issues and are 2 of the issues that need to be fixed.
And tort reform.
If we had fixed these issues; we might not have the mess that we have now with the current law.