Who’s afraid of the big bad conglomerate?

Consumer ad-vo-cates and liberal watchdogs clearly are, as evidenced by the grave concerns expressed over Comcast’s $30-billion dollar merger with NBC Universal, which the Federal Communications Commission finally blessed last week — more than 13 months after the agreement was announced.

FCC commissioner Michael Copps — the lone dissenter in the panel’s 4-1 vote, and a tireless critic of the dangers presented by media consolidation — spoke for many of the merger’s foes in saying the corporate marriage amassed “too much power in one company’s hands.”

The world has changed quite a lot, however, since the apocalyptic warnings triggered by past media mergers, several of which (among them Tribune-Times Mirror and AOL-Time Warner) failed to yield the hoped-for synergistic benefits. And whatever their Wall Street valuations, it’s difficult to argue the new entity has significantly more leverage than other members of the reigning media oligopoly — namely, Disney, News Corp., Time Warner and Viacom, along with CBS and Sony.

To be sure, adding Comcast’s cable systems to NBC U’s content stokes longstanding concerns — dating back to the film industry’s infancy — about combining content and distribution, and the potentially abusive exercise of vertically integrated power.

For that reason, Free Press labeled the merger “deeply troubling,” warning that the FCC has “opened Pandora’s Box, and we can soon expect a whole new swarm of megamergers that will have dire consequences for media and the Internet.”

Still, the motivation underlying the deal appears more pragmatic than that — and in key respects less about going on offense than playing defense.

Mostly, Comcast (which mounted a failed 2004 bid for Disney) desperately wanted a hedge against the vulnerability of cable distribution. Secondarily, there are the potential economies of scale associated with bringing its smaller stable of networks together with those NBC controls, which include USA, Bravo, Syfy and MSNBC.

NBC Sports, get ready to team with the Golf Channel and Versus to pursue major TV rights. “Access Hollywood,” get to know the folks at E! And so on.

Yet even the mighty behemoth that emerges — with its cable channels, millions of subscribers, movie studio and theme parks — must live in fear now of the next wrinkle from Apple, Microsoft or Google, capable of undercutting a sizable portion of its business with a better tablet or new way to wield a mouse. (In this context, there really is something to the threat of a mouse that roars.)

In addition to Free Press, a media reform group, condemnation of the FCC’s approval came from sources as varied as the Writers Guild and the Parents Television Council, which wants a la carte cable so consumers need not pay for smutty channels that might offend them in their monthly packages.

But one suspects Comcast execs would secretly like its shareholders to be as bullish on its prospects as such critics apparently are, since a lot has to go right (for Comcast, anyway) for all the bad things being forecast to fully materialize.

Granted, the Comcast brain trust — led by Brian Roberts and Steve Burke, sons of pioneering TV execs who were practically groomed from birth for these roles — might be smarter than the Tribune or AOL gangs were. Still, the idea of wedding TV stations and newspapers in major cities sounded like a can’t-lose proposition too, and good luck finding the geniuses at Tribune who masterminded that.

In seeking regulatory approval, Comcast inevitably told the FCC and Justice Dept. all the right things about not intending to misuse its size and power. This is the equivalent of an NFL lineman insisting that despite bulking up to 350 pounds, he won’t use the extra size to his advantage on the playing field.

More than just leverage, though, what Comcast really sought to achieve via this merger is diversification. As became apparent during the most recent writers strike, today’s media conglomerates recognize how being too heavily reliant on any one aspect of the business — as Comcast was in cable — makes them more vulnerable to fast-shifting tides and technological breakthroughs lurking around the corner.

Being bigger than everyone else is swell, in other words, but what Comcast feared — and what keeps its brethren among the media elite up nights — is the prospect of being the latest overconfident giant humbled by a kid with a slingshot.