honestly, they should ignore the complaints about adding modded content. especially when it comes to something that doesnt even influence actual gameplay, like the addition of decorative blocks. a lot of mods do an excellent job at extending the contend of the base game while still fitting in with minecrafts style.
i mean look at mods like quark for example, that do things as simple as adding different chest variants for all the wood types.
i have no feelings in either direction when it comes to most of the new blocks added. but i also think they didnt go far enough with the changes.
personally, i would have loved marble and basalt (plus brick, stairs and cobblestone variants) as building blocks like some of the mods add. and imo they could add the entire chisel mod straight into the game without any issue.
if those blocks wouldnt come from mods originally, no one would even notice or complain if they were added to the base game.