The state of Florida requires security officers, body guards, armored car guards, private investigators who are licensed to carry only factory ammunition for duty. I train those guys for their license. Police departments have similar rules. It's about reliability, and guarding against overpressure in the firearms.
I also know about the extent of research done by the FBI on effective handgun ammunition, and I know I am not smarter than the people who spent millions and years developing that stuff. Plus I have killed enough hogs with factory defensive ammo to have confidence in it. Hornady Critical Duty, HST, Sig V Crown, and others have what it takes to get the job done. Hornady 45 acp Critical Duty and Sig V Crown 10mm are especially potent in my experience.
Also in Florida if your use of force is justified under Chapter 782 or Chapter 776 of Florida statutes, you are immune from lawsuit and prosecution. Your state may or may not have similar immunity laws. If your use of force is questionable and does not qualify for immunity, they might try to use what you had for breakfast against you. What you say in public, or what you say on public internet sites could be more harmful that anything.
The shysters can argue anything the want, but ultimately the idea that you are going to be exposed to greater liability for using a handload in self defense is nonsense. If the use of deadly force is justified, whether you use a .22, a 9mm, a 12 ga, or an F350 is only secondary to the question of whether it was reasonable and necessary.