"Toxic" backlinks

[Chancer]

SEMrush told me that one of the sites i'm working on has 5 toxic backlinks, which i should "disavow".
Now i'm wondering, is this necessary?

1 link is from a REALLY spammy site, but 4 are from half-decent industry-related sites. (note: the 5 sites listed us on their own accord)
Also, Google says we have 300 backlinks while SEMrush finds only 160. So i'm not too inclined to trust its recommendations.
Can one of the SEO masters please share their view on 'toxic' backlinks?

My thinking mode here is 'any publicity is good publicity' as far as we have enough backlinks to offset bad links.
I mean lets be honest, if "toxic" backlinks do that much harm, i can dethrone the biggest sites for like $50... surely google knows better, no?

 

[SEOPub]

I would not disavow any links ever unless there is a manual penalty involved. Anyone that tells you to use the Disavow Tool is a fool. You are more likely to do harm than any good.

I wouldn't trust any tool out there to tell you whether or not a link is toxic.

And Google is always going to find more links than SEMrush, Ahrefs, or any other link tool out there. It's very expensive to crawl and index the internet. Google has a lot more resources to do it.

 

[Hielleug]

I Agree with @SEOPub...Google also never recommends this practice.Google algorithm is smart enough to distinguish between bad links and normal links

 

[willsonrobin]

Google’s Penguin update focuses on penalizing the websites that have a toxic backlinks, but only when the amount of such backlinks is high. And Before any penalty, you will receive a warning from Google Webmaster to rectify those issues.