Yeah, I don't care for that first article. If you're trying to sway someone's opinion on an important topic, it's vital to get the words right. It's pyometra. Not pyrometra. I'm a stickler for getting the words right. I left my daughters' new endocrinologist's office when she said HcA1b instead of HbA1c. If I'm trusting you with something I care about, you should get the important terms correct.
Also that first article seemed to imply that spaying your female will cause recessed vulvas, which isn't true at all. Dogs are born with a recessed vulva and spaying too early can mean that the vulva never swells and may remain recessed, but spaying doesn't cause a recessed vulva. Ella has a severely recessed vulva. Usually one or two heats will "pop" things out and the issue is resolved. Unfortunately that wasn't the case for us and I will likely have an episioplasty done when I have her altered.
I will have Ella spayed. She cycles quickly which increases her chances of pyo when she's older. She also had a mild false pregnancy with her last heat. Seems like spaying might be best for her and then we can get that vulva fixed too so she stops having vaginitis so often.