I wouldn’t call them fake, but you’re right in saying that we wouldn’t see them in the same way. It’s not that they’re not visible, but they just look different to us as we see optical light.

For a quick example you can look at a comparison between JWST and Hubble of these galaxies. The Hubble image is FAR closer to what we’d see with our eyes as it’s coloured according to the optical light that’s received. JWST has more false colour as it’s assigning different parts of the IR spectrum their own colours, but you can still see they look almost the same, it’s just that some parts of the image (the dusty bits in the Hubble optical pic) are almost transparent in JWST’s IR.

Even in optical though there’s some inaccuracy. For some telescopes the colour comes from ‘filters’ which tend to single out certain elements and assign them a colour. This isn’t always accurate to real life, but it just adds to the flair of a lot of images.

I 100% would not call them fake though. Infrared light is just as valid as optical light, it’s just that our own eyes can’t detect it. There’s no ‘fake CGI’ involved it’s just that the telescope is capable of seeing more light than our own eyes are capable of.

Just to reiterate infrared light isn’t just looking at how ‘hot’ these space objects are, it is actually the same exact type of light that we can see, just a different amount of energy. It’s like how dogs can hear higher pitched noises than humans can hear; it’s still sound, but our ears aren’t able to pick it up.

Just to explain a little, JWST isn’t capable of ‘piercing through’ any stars. However some stars do emit less light in infrared than other bandwidths depending on their temperatures so some stars can show up as dimmer.

The main thing JWST can look through is interstellar dust clouds as they are mainly opaque in the optical wavelength.

Although I think in this case it was just one of the angels from the film so an added effect