Sorry, but this is going to be a long post.
Possibly you will find this interesting.
Here in Minnesota we have had a recent example of what we are discussing in this thread.
For those of you not familiar with my state, it is often called the land of 10,000 lakes (there are actually a lot more lakes within our borders than that). One of those lakes has recently become a point of contention between various groups in the state.
The lake in question has for the last ~200 years been called Lake Calhoun, named after John C. Calhoun. It was named after Calhoun largely because he was a famous politician, having served in the South Carolina Senate, the US Senate, as US Secretary of State, and as US Vice-President from 1825-1832 under Presidents John Quincy Adams and Andrew Jackson (this was back when the vice-president was appointed by the Electoral College).
Over the years, amongst his normal political activities, he became a bastion of pro-slavery, pro-imperialism, pro-genocide (of the Native American indigenous population), and eventually somewhat anti-US (Federal) government. He died in 1850, about 10 years before the American Civil War, so it is not possible to say if he would have been on the side of pro-secession (ie the South) or pro-union (ie the North).
Naming things after famous politicians has been normal, and acceptable, since at least as long as recorded history (ie more than 5,000 years) so there was nothing wrong with the European descended settlers naming the lake 'Lake Calhoun'. Although Native Americans lived in the area and had there own name for it (Mde Maka Ska aka Lake of White Earth) the renaming had no real effect on the indigenous population since they were not required in any way to use or honor the name. The local settlers of European descent of the time knew the lake as B'de Maka Ska (they had a difficult time pronouncing Mde). The lake was the lake. (This was around 1820 and there were no black slaves in the area at that time, although there was a small number of Native American slaves kept by some of the settlers.)
Eventually, the local Native Americans were either forced to move far away, killed, or rounded up and put on reservation (the White Earth Reservation is one that still exists today). The city of Minneapolis grew up around the lake (illegally appropriating most of its land from the White Earth Reservation), and at some point in time it became a requirement (by law) that the lake be referred to as Lake Calhoun.
Calhoun was a slave owner (owning somewhere around 100 at the time of his death) and was actively in favor of slavery. He was also in favor of killing and/or enslaving the Native American, and it was during his tenure as Secretary of War and Vice-President that the beginning of the planned removal or extermination of the Native American population in all US territories began.
This all happened a long time ago, between 170 and 200 years ago. But, it is important to remember that there are African-Americans alive today who's [great-grand]parents were slaves, and Native Americans who's [great-grand]parents were killed by the US Army, under Calhoun's tenure in Federal government.
The descendants of these slaves and Native Americans have no objection to remembering the history of what occurred 200 years ago. They do object to the people of today venerating Calhoun and perpetuating the idea that Calhoun was a fine upstanding human being.
The current situation here in Minnesota, the US as a whole, and other countries, can (I think) be compared to what happened at the end of WWII and afterward. The idea that tearing down the statues and emblems of the Nazi regime is somehow an act of Jewish (or anyone's) revisionist history, or attempting to hide the real history, would be laughed at by anyone sane. How is what is going on relative to slavery and genocide (by the US or other countries) or hundreds of years of racism (by the US or other countries) any different?
Please do not misunderstand me, I agree that the beginning example of this thread (ie objecting to the inscription on the dogs grave) might be silly - particularly if the objectors realized it was a dog. Do we know if anyone of darker skinned ethnicity actually did object to it?
Objection to the renaming of a lake by a 100% 'white' segment of the general population could also be considered silly. But it took a popular movement to get it started, continuing the movement for over 3 years, and defeating a lawsuit filed by people who opposed the name change that went all the way to the Minnesota Supreme Court, before the name could be changed officially.
I'll put my horse back in the barn now.