That's because those elements have been ingrained in the game for years, and it's unlikely that anyone will suddenly start criticizing something that's been part of the game's fabric since the beginning. Many of these jobs are also staples in the Final Fantasy series, having had ample time to establish themselves as core components. Pictomancer, on the other hand, has only appeared in one mainline game and perhaps a few lesser-known spin-offs. The reason these established jobs aren't under as much scrutiny is simply because they're no longer the new kid on the block. It's Pictomancer that is right now.
Moreover, singing, card reading, and dancing are just one aspect of these jobs; they encompass a broader range of abilities. Bards, for instance, combine singing with archery skills, while Astrologians wield cards alongside their healing abilities, creating captivating stellar effects. Even Machinists, with a single odd skill, boast a range of impressive abilities that overshadow any perceived absurdity.
In contrast, Pictomancer's identity seems limited to painting, which, based on what little we've seen, doesn't immediately captivate. Until we see more of its repertoire, it's hard to gauge its potential beyond this singular focus. Another aspect that might have deterred some viewers was the exaggerated flamboyance showcased in the Pictomancer trailer. It possibly overshadowed the game's essence for some. While arguments about its silly nature may seem disingenuous at times, it's understandable why Pictomancer is receiving such scrutiny while the others aren't. Also, it's worth noting that Dancer initially faced scrutiny for its unconventional nature. There was a period on these forums where some found it challenging to reconcile the idea of dancing amid battle despite being a reoccurring job in the series.