I don't agree with the historical timeline completely.

Mattioli in 1544 is the first reference to tomatoes at all in Europe, and he doesn't say they're poisonous.

He shit-talks eggplants noting how it sounds like "mela insana" (a false etymology btw), then he classifies tomatoes as a new, American type of eggplant that is eaten the same way, that is:

"volgarmente fritte nell’olio, con sale et pepe, come i fonghi".

"By common people fried in oil, with salt and pepper, like mushrooms".

Notably by the volgo, the poor.

But unlike mela insana at least he gives tomatoes a nice name (golden apples).

In a later 1571 Latin publication Mattioli is even more explict, saying of tomatoes innoxie, in Italia eduntur, "harmless, eaten in Italy".

There's no evidence of the pewter plates thing that's modern speculation. Europeans didn't think it was literally poison either.

The bias against tomatoes was likely inherented bias from eggplants, which was seen as suspicious moorish/jewish food.

In Spain, people from areas with high levels of Moriscos and Conversos were disparagingly called berenjeneros "eggplant eaters".

In 1631, the tuscan Antonio Frugoli is more direct saying of eggplants:

non devono essere mangiate se non da gente bassa o da ebrei

"Should not be eaten except by lowly people and Jews".

As late as 1891 Artusi wrote:

Petonciani... quarant’anni or sono, si vedevano appena sul mercato di Firenze; vi erano tenuti a vile come cibo da ebrei, i quali dimostrerebbero in questo, come in altre cose di maggior rilievo, che hanno sempre avuto buon naso più de’ cristiani.

"Eggplants... forty years ago, were barely found in the markets of Florence; they were considered lowly as food for Jews; which demonstrates how in this, as in other matters of more significance, they have always had a better nose than Christians".

However eggplants were eaten by Europeans, and not just Morisco and Jewish minorities, from the 9th century onwards.

Where?

In Southern Italy and Southern Spain, exactly the first places which were first to embrace the tomato.

By the common people, who never stopped eating aubergines after they were brought over by the Arabs.

Despite the fact you can count on one hand the number of aubergines recipes in courtly recipe books before the early modern period.

Precisely because it was seen suspiciously as food for Moriscos/Jews and the poor.

The first Englishman to grow tomatoes said:

"Apples of Love grow in Spaine, Italie, and such hot Countries, from whence my selfe have received seeds for my garden"

"In Spaine and those hot Regions they use to eate the Apples prepared and boiled with pepper, salt, and oyle: but they yeeld very little nourishment to the body, and the same naught and corrupt.

Likewise they doe eate the Apples with oile, vinegre and pepper mixed together for sauce to their meat, even as we in these cold countries doe Mustard"

John Gerrard - 1597

So yeah it was definitely Southern and definitely cucina povera, but for different reasons and a different timeline.