I don't know which part of your comment you're saying sarcastically, but I presume you're referencing the fact that Redis uses up a lot of memory.
This is because Redis is a caching database, and pulls the data into memory for it to be faster. This is by design.
I believe the sarcasm is around Sentry and implying that it's redis usage is poorly optimized. I'm not familiar with Sentry, but it looks like the self hosted version makes use of redis as part of it's underlying stack.
I recognize our (Sentry’s) over-use of redis. Also doesn’t make us particularly happy. Can’t promise that this will get significantly better but the desire is there at the very least.