I think this is overstated. Obviously it’s your opinion and if it was your car you can do as you like.
But you can absolutely weld on UCA’s like that and have it be more than strong enough for continued, long term use- if the welds are good.
Now, not knowing the history on those particular UCA’s, who did the work, or how long ago, etc, would lead me to replacing them if it was my car. But that’s not the same as saying those UCA’s aren’t structurally sound. I’m not gonna say they are or aren’t based on a couple pictures on the internet, but that kind of work can absolutely be done safely if it’s done correctly.