I think keeping the art as it was produced is important but there is also a good history of modifying art to produce new art too. In the digital age, we aren’t losing the original art so it seems even stranger to be against modification of the “original.”
However, just applying a simple filter (or single transform without effort) definitely feels derivative to me.
I have always viewed them as "more relatable". People may well be biased to think of more relatable things as more true, but I don't think that is the fault of the colourisation or how it is presented.
However, just applying a simple filter (or single transform without effort) definitely feels derivative to me.