Ironhide doesn't think he knows of anyone who would call Ratchet selfish.
Through the years, and numerous battles, the medic has given up his own parts in order to keep his comrade's alive and running at optimal levels. He was created for this, his body continually regenerating surplus parts which he will, inevitably, give to save one of their lives.
So, no one would use the term selfish in a sentence with Ratchet's name.
But Ironhide has known Ratchet from the time he was a sparkling, has watched the mech grow into the finest, most-skilled medic the Autobots have ever seen and he knows what to look for…
He knows that, whenever a new medic showed up in their camp, Ratchet would find some logical reason for them to be assigned elsewhere and fast. After all, he didn't need assistants to trip over.
He remembers the time Jazz came back from a recon mission blinded by an unexpected solar flare. Ratchet claiming that their optic relays were incompatible; it had taken weeks to create from scratch, new relays for Jazz. He'd been afraid that, blind (even temporarily), he'd be useless.
More recent, Ironhide recalls Bumblebee's losing his voice. The small mech had confided to Ratchet that he was terrified his new voice wouldn't be his. And that had been the perfect excuse. Ratchet didn't heal Bumblebee immediately; instead he'd had the young mech return any number of times through the years for 'voice therapy'.
After awhile, Bumblebee spent time with Ratchet because he wanted to and because he could see how lonely the other mech was.
Jazz, too, made a point of dragging Ratchet out of the med-bay for target practice, claiming he thought his optics were acting up.
Ironhide watched his comrades slowly and surely teach their medic that he was an indispensable part of the team. He was their friend, family, and they cared about him.
Ironhide thinks, 'Now, Ratchet won't have to find ways of hoarding our attention. The friendships he's been looking for have been there all along.'