Hi there!
Don is absolutely right that spam score values varying by subdomain, as that's how we make distinctions for the metric.
With that being said, spam score of a given subdomain is not particularly easily influenced by the types of sites that are linking to it. Most of the 17 possible spam flags (which can be viewed here: https://moz.com/researchtools/ose/spam-analysis/flags?subdomain=www.penn-criminallawyers.com) are reflective of on-site factors within the subdomain itself. So, while I agree that spam score is not particularly well-adjusted to speak to the fact that http://www.penn-criminallawyers.com/ has some serious issues with their inbound links, it's worth noting that they didn't necessarily have to have cultivated all of those backlinks for themselves. I'm certainly not trying to go down the rabbit hole of spam conspiracy theories, but simply accounting for the fact that anyone can create a link to any site (unless disavows are involved), and it could be rash to judge a subdomain's "spammyness" based purely on their inbound external link profile.
Spam score is based on these 17 flags based on correlation (not causation) research that was done by Moz's data scientists, and it also makes the acknowledgement that there will be penalized sites with low spam , as well as non-penalized sites with a high spam score. For more context on that, I'd highly recommend that anyone looking into using spam score watch this explanation from Rand on the topic: https://moz.com/blog/understanding-and-applying-mozs-spam-score-metric-whiteboard-friday
To clarify, am I advocating that http://www.penn-criminallawyers.com/ is not a spammy site based on what spam score says? Nope. I'm not even speaking to that topic at all. For all I know, it certainly could be (and maybe I'm even inclined to think it is).
Am I saying that spam score is a value you should take at face value without doing any digging into the specific subdomains, themselves? Certainly not. I would stress doing serious research any time you're looking into spam, credibility or disavowing; it's simply there to serve as a potential source of guiding information.
Hope this helps!