There are some people that deserve it, but they were human too, with faults like the rest of us, they just pressed on with something and achieved more.
On the other hand, for historians, sculptures of individuals have shown us what public figures looked like. I just don't think we should worship them. It's God's little joke that pigeons poop on them ;)
Bill Henderson creative commons
"... The blacks are very quiet here now, poor wretches. No wild beast of the forest was ever hunted down with such unsparing perseverance as they are. Men, women and children are shot whenever they can be met with ...
I have protested against it at every station I have been in Gippsland, in the strongest language, but these things are kept very secret as the penalty would certainly be hanging.
... For myself, if I caught a black actually killing my sheep, I would shoot him with as little remorse as I would a wild dog, but no consideration on earth would induce me to ride into a camp and fire on them indiscriminately, as is the custom whenever the smoke is seen. They [the Aborigines] will very shortly be extinct. It is impossible to say how many have been shot, but I am convinced that not less than 450 have been murdered altogether...". Gippsland squatter Henry Meyrick wrote in a letter home to his relatives in England in 30th April, 1846.
Much of the genocide of the Aboriginals, (and slavery of Torres Straits and other peoples up North) in Australia has been swept under the carpet , ignored in history books, and hidden by family historians. (A Scottish ancestor of mine was one of the original settlers of this district. I don't know if he was a member of McMillan's Highland band posse or not. He was a shipwright, which was needed, so I imagine too busy . ) We cannot criticise apartheid in South Africa, or slavery fought for by General Lee, without taking a good hard look at ourselves, and what we have erected in our public spaces. If it's a cairn to mark a significant route, then fine. If it aggrandises a racist bully, not fine.
If Angus McMillan's life choices were weighed by God and found not to be wanting, in the balance, then let's leave the memorials up as his route markers, being an explorer. However, having an electoral division, scout halls, streets and public schools etc named after him , as they are, might be due for reconsideration. Certainly I think the aboriginal community would appreciate it.
In 40,000 years, before white settlement, I don't think they put up any large figurative sculptures celebrating any particular persons. They also didn't destroy their environment. Who was more civilised, us, or them?