I don't know why you get the feelings that you do.
From the little that I know, refusing to acknowledge the relationship is a shabby thing to do.
I suspect that some who would agree with me are chronic detractors of the of the President, incapable of balanced judgment, but that does not mitigate the ignominiousness of such a denial.
I hope that the President comes to acknowledge his granddaughter as has his son.
Hunter Biden has, reportedly, been paying child support and health insurance for the girl, and I hope she is receiving whatever emotional support she needs and deserves.