He had his public rant at the funeral
It was hardly a "public rant"
For all those that don't remember what he said in his eulogy at the funeral here is the transcript. I remember, at the time, cheering him on because it was a most beautiful speech. I'm old so I have a distinct memory, I can remember stood there in my kitchen listening to him.
There is only one small paragraph that everyone gets riled about and I honestly think there is nothing wrong with it. I applauded him at the time. Is it really so bad? I don't think so. Please do read the whole transcript, not just what some would consider 'the rant', it summed up Diana.
And beyond that, on behalf of your mother and sisters, I pledge that we, your blood family, will do all we can to continue the imaginative way in which you were steering these two exceptional young men so that their souls are not simply immersed by duty and tradition but can sing openly as you planned. We fully respect the heritage into which they have both been born and will always respect and encourage them in their royal role but we, like you, recognise the need for them to experience as many different aspects of life as possible to arm them spiritually and emotionally for the years ahead. I know you would have expected nothing less from us
https://www.bbc.co.uk/news/special/politics97/diana/spencerfull.html