No, they're quite open about the capabilities of the optics (see https://webb.nasa.gov/content/forScientists/faqScientists.ht...). It's just that Europa is very far away.

Webb's mirror system has an angular resolution of about 0.1 arcseconds. Earth is currently about 630 million km from Europa (Webb is only 1.5 million km away from earth). Because the sine of theta is approximately equal to theta for values of theta near zero, you can get the diameter of a 0.1 arcsecond cone at x km from Earth by multiplying by 0.00000485 = sin(2pi/3603600).

0.1 0.00000485 * 630000000 = 305 km

The article says the pixels are about 320 km, so the math works out pretty close (for astronomy).

Those magnificent images of black holes and galaxies that are way more distant, but also way way bigger. This isn't downscaled when you compare it to gorgeous, sharper images like those at [1], a 340 light-year wide multi-image mosaic of the Tarantula Nebula, which is "only" 161000 light years away, that width is 1/500th the distance and Europa's width is 1/20,000th the distance.

In space, intuition about distances that you've built up from using your eyeballs on human-scale terrestrial objects just doesn't work, you've got to do the math.

[1]: https://www.nasa.gov/feature/goddard/2022/a-cosmic-tarantula...