The post you're quoting wasn't invented in a vacuum; they're responding to the frequent baseless claims from certain political activists suggesting transsexual individuals are sexual predators and accommodating them in society puts people (particularly children) at risk of being abused by transsexuals.
This prejudice happens despite a dearth of evidence suggesting transsexual individuals commit sexual abuse at rates higher than the average population, and despite a mountain of evidence showing plenty of non-transsexual people committing acts of sexual abuse.
Heck, if you want to realize how ridiculous of a discussion the transsexual bathroom thing is, just think about the fact that straight men can also sexually abuse women in bathrooms. It's not as if there is some magical barrier that automatically prevents anyone with a penis from entering a women's bathroom, but once they're declared as trans, they're able to bypass this magical penis barrier ... it's a ****ing room with a door, anyone (including men), with any intention, can enter, trans or not.
So, yeah, if you have some folks loudly (and wrongly) condemning an entire demographic of people without any good evidence, pointing the finger at them, all too often ignoring those actually committing acts of abuse, it's only fair (and expected) to point out the wrongful prejudice.
I agree with your post stating this is fundamentally a human issue; humans of all types can be flawed and do bad things, that's absolutely correct. I wish the folks demonizing transsexual people realized this.