It wasn’t newer than the entire ship he was on, though, and he didn’t have that reaction to any of the other tech – including the insanely powerful warp engine that was likely even less tested and capable of destroying anything in a significant radius.
I’m not saying he was phobic, but he’s more cautious than anyone else in the scenes where this is emphasised, like it’s a character trait.
Did they ever stop having accidents with them? Even in LDS they have problems. The transporter is really a plot device masquerading as a suicide machine.