I think people are being unnecessarily harsh on the OP who is going through a significant loss and possibly not thinking rationally. There also seems to be a couple of issues at play here. First of all, it does seem correct and usual practice, if also slightly harsh, for companies to impose boundaries for compassionate leave and close family makes sense. What needs to go hand in hand with that however, is an understanding that leave can be taken at short notice and without quibble when an employee needs or wants to attend a funeral for someone who does not fall into that compassionate leave category. Denying a leave request under these circumstances is truly heartless and does not make for good staff morale.
I'm currently being frustrated by a similar(ish) situation. My lovely uncle died and the funeral is this week. Work is really busy at the moment so although it is really important to me to pay my respects, I had planned to go to the service only, forgo the wake and work the rest of the day. The funeral is relatively local and at 1pm so I can be there and back in just over two hours, one of which should be my lunch hour (ha!) anyway. I spoke to my boss to explain the situation and suggested that, when I come back to work, I stay on for an additional hour/90 minutes to make up the time or I would be happy to take it unpaid but no, I am being forced into annual leave. I can't even just take a half day annual leave, because of the timing of the funeral and the fact that it doesn’t map correctly on the two halves of the day, I am being forced to take a full day's leave. On the one hand, great - I can grieve properly and attend the wake but on the other, I am just storing up loads of work which then needs to be competed in 4 days, including having to reschedule meetings, which I otherwise could have attended in the morning and late afternoon, and cause inconvenience to others. To make matters worse, I regularly work unpaid overtime because of the workload and amassed an additional 9 hours last week anyway. The way I see it, the time is already in the bank and additional time will be worked anyway, so I'm just adding to this by taking a day off when I had tried to do the right thing by me, my uncle, my extended family and my team by reducing the time off.
Ironically, the reason I am trying to conserve my annual leave is that my dad is ill and lives abroad and I am aware that we could lose him over the next year. I will get compassionate leave for this but it won’t be enough to sort out the funeral, get my mum settled (she has health issues too and my dad is her carer), plus all the legal issues surrounding an ex-pat death in the country in which they live (I have heard horror stories from other adult offspring in my situation). I know I'll have to take considerable annual leave to add to the CL when the time comes, otherwise I'd have to take it unpaid and will really struggle to keep afloat so am trying to not to eat into AL too much at this point. I was therefore trying to do the right thing by my uncle without having to trade off his definite funeral for my dad's possible death.
The other thing I have noticed is that people seem to subconsciously categorise non-CL as a situation not requiring compassion (and, by extension, AL = holiday = fun!) so I wonder if the OP is suffering from colleagues/bosses, just shrugging off her loss and therefore minimising her grief. I do think that there is a middle ground and employers/bosses need to be mindful of the fact that people may well be upset by a death even if it not their parent/spouse/child. I small word of kindness and acknowledgement; "I'm sorry to hear that", "hope all goes as well as it can at the funeral etc" goes a long way.