The email feedback, particularly from folks in Boston—a hometown I happen to share with both Hubspot and Lyons—basically boiled down to:

1. Lyons, who is extremely critical of Hubspot, doesn’t know what he’s talking about.

2. They haven’t read the book yet.

To be fair, some of these folks may already have seen a review of “Disrupted,” or perhaps read this exclusive excerpt that Fortune recently published.

But, in general, it seems to be a bit of circling the wagons around one of the few local tech companies that has gone public in recent years, let alone at a valuation in excess of $1 billion. Or maybe they’re friendly with Mike Volpe or Joe Chernov, two senior Hubspot executives who were fired (technically, Chernov resigned) after allegedly trying to obtain a draft version of the book before publication (Lyons portrays both as villains, and that’s before the epilogue discussing their fates). Or maybe they’re Millennials who take offense at the idea that they could be discriminating against a 50-something like Lyons, or believe that he is actually the one exhibiting bias against younger workers.

To be equally fair, I probably see a bit of myself in Lyons. We’re both cynical (perhaps arrogant?) journalists who have been doing this job long before Facebook (FB) or smartphones, let alone Hubspot. I’m a decade or so younger, but the notion of someday needing to take a quasi-PR job to feed my family is nauseating.

But whatever we bring to the table, my suggestion stands: Read this book if you work or invest in tech and, in particular, tech startups. And not just for the tales of corporate intrigue, hypocrisy, and ridiculousness that have caused HubSpot and its allies to get so hot under their collective collar.

Lyons accurately illustrates the tech world’s obsession with hiring young (read: cheap) labor, while simultaneously exposing how it often doesn’t have their best interests at heart. Just because you can trick someone into thinking a wall of candy dispensers is better than a bit of extra cash doesn’t make it so. And options don’t matter if you get burned out before they vest.

He also makes a strong case for how all of that young labor, when increasingly wrapped up into an over-arching “corporate culture,” creates subtle age discrimination that these employees won’t recognize for years to come.

He tells the story of a 2013 New York Times piece about HubSpot, in which co-founder and CEO Brian Halligan said: “In the tech wold, gray hair and experience are really overrated.” When Lyons expressed offense, he got a lot of blank stares:

Some of my HubsSpot colleagues seem genuinely baffled by my complaint. One of them ― white, male, in his twenties—sends me an email asking why I’m so angry. I tell him that in retrospect I am not so much angry as I am disappointed…

I ask my young, white, male colleague to imagine that instead of saying older people (gray hair and experience) are overrated, Halligan had said that gay people are overrated, or women, or African-Americans, or Jews. Imagine Halligan saying, “We’re trying to build a culture specifically to attract and retain white people, because when it comes to technology, white people do a much better job than black people!”

“But he didn’t say that!” my colleague responds. “He didn’t say anything about gays, or women, or black people.”

As the Bible says: Jesus wept.

This not only is a real (albeit virtually ignored) issue at tech companies today, but is going to become a much larger one as digital natives continue to age. Imagine today’s 20-something denizens not only of HubSpot, but of all Silicon Valley tech companies in 30 years. Will most of them still want to work in tech? If so, will they be considered employable, or no longer “culture” fits? Will they look back and regret having helped to dig their professional graves?

Remember, Roger Daltrey and Pete Townsend might have wanted to die before they got old, but then they didn’t.

(note: if you didn’t get that last reference, perhaps it means you’ll take my job in a few years.)