Why don't you just leave the ads in, and then people won't be mad at you?

Giving credit to the original author – which I understand you did in the post body – is advertising only in the most benign sense. It is not intrusive; it is not misleading; it is not manipulative; it is not malicious; it is not meaningfully harmful in any way.

I understand hating watermarks. But this isn't someone slapping an iFunny or whatever bullshit brand onto an image completely unearned like a barnacle; the artist created a work for you to have for free (as in beer, and given memes, mostly as in freedom too), and the only thing they're asking is that you preserve this small bit of credit. No, it's not charity, but – speaking as someone who does volunteer work nobody will ever materially compensate me for – whoooo cares?

In an Internet awash with faceless, generic slop that nobody and everybody created at the same time, an artist's watermark is one of the few ways people can attach an identity to their work. You definitely realize that removing credit from the image and transferring it to the post body isn't identical – else you wouldn't do it. Yet you're still advertising for them, just in an intentionally kneecapped way that profits a known-malignant, multibillion-dollar corporation. What you're doing as a substitute is somehow worse – transferring part of the advertisement to RDDT (136.18).

No rational way of looking at this makes sense.