He's from India - why would he care? I wouldn't - @Noonecares245
It matters because it's a huge gaffe. If he's that tone-deaf to the values of most British people then what else is he oblivious about? He painted himself as badly out of touch.
Also, India's contribution to the allied war effort was the biggest volunteer army in history (numbering in the millions). Perhaps you should get off MN and read a few history books.
Now compare Sunak's approach with that of Nigel Farage who everyone loves to hate. He attended in a private capacity, as he does every year - not just the big anniversaries, and he attended the entire event. He was seen chatting casually with many of the other attendees - because he understood the importance of it, not for reasons of vacuous PR. There are genuine reasons why he has the common touch.