The left have lost plenty of defamation cases to conservatives in court, a lot of them posted on here. Look it up.
Obviously, not enough big cases like the one with Sandmann. Sandmann had no power, he was a kid, that one was kind of a no brainer for a win.
Many of the cases the left is bringing are not defamation cases. They are cases with trumped up charges or set ups against political opponents that are criminal cases. Our guys, with the exception of RINOs who collude with RATs, never do that.