People do all kinds of things in their private life, and - as long as it's all consensual, and involving adults, in private - that's absolutely fine with me. Even if it involves fetish stuff that I find deeply unsexy. It's your private time and your business.
But if you bring your fetish into work, that's really inappropriate. Involving other people in your kink without their consent is not OK.
If you bring your fetish into work and take time to entertain yourself in the loos with it, that's way, way beyond really inappropriate.
If you work in child protection campaigning, and bring your fetish into work, and take time to entertain yourself in the loos with it, and take a photo of yourself while doing it, and upload that photo onto the internet, then you probably need to consider whether a career in child protection is really for you.
(And if you are doing this while working on campaigns about abused and neglected children, you should not be surprised when people ask what made you so aroused.)
And dear NSPCC - who I used to have a direct debit to, and who used to be in my will - people objecting to this are not being homophobic or "bullying". Many of who are objecting to your staff member's actions are ourselves gay. We just seem to have a better grasp of safeguarding than you do.