Leaving Tolkien aside, both half elves and half orcs have been a popular thing in D&D itself now for fifty years. That's enough reason for me to feel they should still be available. It is always easier to give than to take away, and people notice when something has been taken, as it has here. Even more unusual, as there is no basis for "unfortunate lineage" half orcs in the new edition, where orcs appear to be friendly nomadic gauchos worshipping a Gruumsh who feels a bit like a fatherly Woden. And for the half elves, I have never heard of any negative connotation in relation to how one might end up with a human and elven parent, something that I feel accurately reflects how real racial and ethnic mixed-race people (an exceedingly common and normal thing in the real world) come about. So fantasy representation of such is actually a healthy expression. In other words: don't ditch the concept of mixed-race characters, ditch the outdated concept that it all has to happen due to bad actors among the parents.