During DD's playing days, pitchers had certain catchers that were their favorites. Why? Some catchers couldn't "frame" and would turn strikes into balls because they couldn't stick the pitch and would let the ball take their glove outside of the zone. Pitchers need to be confident in who is receiving. I would hear it from the pitcher's parents when Catcher #2, or #3 was behind the dish. I would nod and tell them those catchers need innings too.I agree it's much easier for a catcher to turn a strike into a ball. A lot of umpires tend to hate when catchers flip their glove over when catching lower pitches; the same pitch caught without the glove flip would be a strike. Similar to dropped strikes sometimes getting called balls even if they were strikes, or when catchers don't set up close enough to the plate and let the ball get too deep leading to them being called balls when they wouldn't have been if they snagged it closer.
Some umpires don't care about the catcher's mechanics (and shouldn't), but there's a good amount that do, and will punish the pitcher because of it.