Well overall, using these techniques has probably resolved a ton of investigations where the leads ran out and it being an overall positive. I think it would still be better that DNA from these sources cannot be used in trial. So a DNA match can give you a new angle to find other elements, but the fact DNA was used to find a trail shouldn't be admissable.
I guess the saying "better 100 guilty people go free rather than an innocent man should suffer" applies though.
My bias though is probably skewed through the media I consume. I do watch a lot of channels like Lackluster YouTube videos (shows corruption and double standards in policing). I do try to balance it out with channels like Code Blue Cam which does highlight good policing too, but I would say I have an inherent distrust with policing nowadays.