I'm not clutching at straws, I have no skin in the game as my office shuts for Christmas so I get it off regardless of my personal circs but as a HR professional I am answering a question about how childlessness could come into it.
It may be a tiny risk and it may be difficult for a childless person to link to a medical conditions/disability but it is a risk nonetheless and one a childless employee MAY make.
Other risks that also exist have already been covered on the thread - sexual orientation and age discrimination.
Disgruntled ppl will clutch at straws, working in HR has taught me that. Whether they would be successful at a Tribunal or not doesn't really matter for most businesses - the time and costs defending it still rack up and cause headaches - whether it's morally fair or not, it's not a policy I would be sanctioning where I work as it's got all kinds of potential headaches, whether legally defensible or not
Edited to say your dog analogy doesn't make sense , how would a none disabled person claim discrimiation?
To give you a real example where childlessness could be indirect discrimination - cancer is covered under the EA. If I've had my ovaries removed because I've had ovarian cancer and that's also the reason I don't have children then there's my link. Obviously it's a tiny risk because I doubt that applies to many ppl but i was answering the question on how childlessness could link to discrimination.
The far more obvious risks are age and sexual orientation. If I'm 20 and gay I'm significantly less likely to have children and obviously don't have grandchildren so best chance I have is 2 out of 4 categories, than a 40 year old straight person.
Like I don't know a single competent HR professional that round touch something like this with a barge pole - why take the risks, there's enough ppl on this thread saying they'd complain , like no thanks, don't want that on my desk regardless of any personal feelings on children having Christmas with their parents