I agree with you that the blue channel is saturated in this image.
I'd say that much of the Tadpole Galaxy isn't as dominated by young blue stars as the APOD suggests.
Normally, when you see a well-resolved image of a galaxy, you'd expect the bluest parts of it to be "prickly with stars like a hedgehog". That is because the bluest color will come from individual hot stars of extreme brightness. In a good picture, we can see these stars as individuals.
Less blue and completely non-blue parts of a galaxy will look smooth. That is because the light from these parts comes from huge numbers of relatively faint stars, which don't stand out individually.
If you take a look at the Tadpole Galaxy, you can see that there are bright individual stars in the long tail. These parts are undoubtedly blue. On the other hand, the outer "ring" on the right side in today's APOD is very smooth. There are few or no really bright stars in it. Even so, it looks clearly blue.
Can this part of the Tadpole galaxy be blue at all? Yes, it can, because it could be dominated by stars similar to Sirius, Vega and Procyon. These stars are neither extremely bright nor extremely blue. They are, however, bluer than the Sun, and
if the light from this part of the galaxy is dominated by Sirius-like stars, then it is okay to show it as bluish, in my opinion.
On the other hand, it is also possible that this part of the Tadpole Galaxy is dominated by Sun-like stars. If that is the case, then the blue color is not okay.
The center of the Tadpole Galaxy is seen as very faintly yellowish. We have every reason to believe that this part of the galaxy is redder than the Sun. But it looks hardly yellow at all.
To summarize, the blue parts of the Tadpole Galaxy look very blue, while the reddish parts of the galaxy look barely yellow at all. So the color balance of this picture is definitely very blue.
Ann