Space flight is spectacularly dangerous, and US launch vehicles have a particularly gnarly safety record. Some paranoia is probably warranted.
Challenger and Columbia were lost due to institutional ineptitude. The engineers that were the manufacturer of the SRBs on Challenger specifically warned against the cold temperatures and were overruled. People noticed the foam shedding issue with the space shuttle many years before the Columbia incident. The space shuttle was a catastrophic clusterfuck of a pork barrel political design. There was actually no launch escape system or possibility of recovery from early launch phase anomaly once the SRBs were lit, until they burned out (unlike the launch escape system on Soyuz, Apollo, Dragon2, etc).
The space shuttle had a ridiculous number of moving parts and degree of complexity compared to a Dragon2 on a Falcon9 (or a Soyuz on top of its booster)
The soviet union and russia have had zero fatalities since Soyuz 11 in 1971. I would actually venture that at this point it might be statistically safer to fly along as a passenger in a modern Soyuz mission than to fly as a second passenger in some sub-500-hour pilot's kitbuilt piper cub clone.
But Wikipedia tells me that the next Soyuz to go up will be #142, counting from Gagarin. In the hypothetical world where (say) the Mir crisis had been fatal, Soyuz would have a lifetime success rate almost exactly the same as the Shuttle's.
Even if the new ones are much better, we don't have the statistical power to say. Gimme the kitbuilt Piper any day.
The Soyuz-success/failure manned rate is about the same as the space shuttle, though a bit higher but with successful escapes and launch aborts. If you start comparing casualties the space shuttle loses massively as only 4 cosmonauts have died, all in the decent stage (either crashed or died on entry) with the R7 and derivatives as launch vehicles and Suyuz or Voskhod as name.
To be fair, the total of the R7 family (which is skewed since there are way more failures in the early days than after the 1990's for all kinds of rockets) is 137 vs 1755 or about 7 % vs the 1.5% of the space shuttle.