It’s a hyperbole. It’s not unethical. But many people don’t like it/hate it.

1. An image is just more expensive than text. Text is usually ~1 byte per character. An uncompressed image is ~3bytes per pixel. Of course, most images are compressed, and compression does a lot of heavy lifting. But still. Also, you don’t need to uncompress plain text. More amount of bytes means more storage expense, more network expense, and worse user experience due to latency.
2. We have plenty of tools that work for text. You can copy-paste it. You can easily edit it with just a keyboard. It is easily configurable via fonts and font sizes.
3. Accessibility: text can be read by screen readers. Images (without alt text) cannot. Maybe there are some fancy screen readers that OCR images, but then it’s the case of point 1.
4. Text is easily indexable. Which means that it’s searchable. If the reddit search tool were any good, it could find the post. Not for images. Alternatively, 3rd party search tools such as google and DDG work.

There’s probably many more points.