Though backlinks are not as important for the continued success of a given website's placements on SERPs as they were prior to a core update recently issued by Google, it is argued that there is still some merit in maintaining a moderately thorough backlink profile. One reason this might be the case is that "toxic" backlinks continue to be implemented across the web that might possibly lower a particular website's potential for rankings through mere association with them, even if those backlinks are not necessarily that site's own fault.
Of course, Google is set up so that it attempts to penalize all instances of backlinks deliberately set up by the site's owner through surreptitious methods. A logical reason why backlinks worthy of punishment might appear on a certain site's behalf would be that the site owner may have prompted low-quality external domains to set those backlinks up, perhaps by purchasing them.
However, it is an issue commonly faced by site owners everywhere that the backlinks that end up emerging in response to their sites' building prominence in the public discourse will invariably include backlinks from domains that have nothing to do with the site's subject matter. Meanwhile, deliberately toxic backlinks can be instigated by malicious competitors and troublemakers. Either way, this will end up driving up an unwanted "Spam Score" value that will be reported within the popular SEO utility suite known as Moz when it is used to assess a website's current prospects for SERP positions.
There is a procedure available to site owners that allows them to disavow especially egregious backlinks by entering their domains into Google Search Console. However, because backlinks are less significant as methods of influencing SERP rankings nowadays, it is more commonly advised to simply focus one's efforts on creating strong and relevant backlinks in order to have a solid backlink profile to speak of. Moz' metrics will end up displaying Spam Scores with mild percentages at best, regardless of which website is being assessed. Therefore, fully stamping out all instances of spam backlinks pointing to one particular website would not even be possible. For more information click here https://www.reddit.com/r/SEO/comments/nbbjed/how_to_reduce_spam_score_of_a_website/.