The controversial part is equating “centrist” to “least biased”. Being a centrist is a political position, and like all others, it comes with its share of bias.

Beside, the “center” views depend in the country, year, and even on who you ask. A man can go from right wing to center to left without changing his stance on anything if the countries politics shift right, and the reverse is true. There were right-wing communists in the USSR, tho they were not right wing by capitalist standards.

There are objective ways to judge a news outlet: Whether they name their sources, whether they’ve been known to post updates and errata when an info they’ve posted turned out wrong, whether they’re independent, state-funded or dependent on a company, and in the two later cases, are the state or company known to make use of their influence on the news…

And the website quoted by the bot accounts for some of these… But political positioning, while worth mentioning, shouldn’t be used to calculate the reliability of an outlet. Doing so doesn’t fight bias, but just favors some bias over others.