The reason Thomas was put on the SC was...
...NOT because he was the most qualified jurist. He wasn't.
...NOT because he was the most qualified black jurist. He wasn't.
...NOT because he was the most qualified black conservative jurist. He wasn't.

He was the most qualified black conservative with reliable but obfuscatable views on abortion & other subjects, and was young enough that he'd stay on the court for decades.

The Democratic senators were initially ready to give him a pass, since 1) they didn't look forward to another SC nomination battle, and 2) initially the black community was receptive to Thomas -- not enthusiastic, but not inclined to oppose -- and a fight against him wouldn't be well received.

At the time I thought Thomas should have been voted down just because of his lackluster record and ignoring conflict of interest (Thomas failed to recuse himself in a case involving the Ralston Purina company, where his political mentor Sen. John Danforth owned millions in stock and had brothers on the board of directors. Thomas' decision in favor of Purina directly benefited his pals).

Black opinion didn't shift until later in the process, after Thurgood Marshall made his "a black snake is still a snake" comment. The senators were finally forced to take a harder line when the harassment charges leaked out, and giving Thomas a pass would piss off another Democratic constituency: women fighting workplace harassment.

But all that happened too late: by that point conservatives were ginned up in support and the rest of the establishment didn't want another high-profile fight, so the Thomas hearings were kept to a he-said-she-said with Anita Hill (Angela Wright was shunted off to the side), giving the senators their excuse to just put it behind them.

So here we are, a quarter-century later, and he's still a lackluster jurist who ignores conflicts of interest, and is a reliable conservative operative in the courts.