There was no compelling reason to protect the Earth from the Tollan. They had been cleared by the docs and, more importantly, they wanted to leave Earth! As for the Goa'uld threat, it'd be nice for some help from them, but it's not surprising, really. When does the group in power feel compelled to toss off its technology for one side in a war without any compelling reason to believe in their righteousness, especially considering the fact that despite what was told them, we were, in fact, imprisoning them (at least we thought we were) and flashing our weaponry at them every chance we got?
The Tollans were right about sharing their technology with us. Everyone knows that we'd use it to bully the rest of the world and it coud easily get into multiple hands and consequently, could lead to planetary destruction just like what had already happened to the Tollans. Forget the Goa'uld. We'd take care of destroying Earth ourselves. The Tollan were solid about the decision not to share.
Now, they could have dropped some of the attitude, particularly with Tuplo who was extending to them a very nice invitation. But upon reflection, it occurred to me that though the Tollan may have been more technologically advanced than us, there may have also been consequences to this. Their emotional capacity seemed different to ours.
I believe this was reflected in Omac's seemingly bitter and "obstinate" attitude. I'm not so sure he meant it personally. I thought the Tollan were, perhaps, less emotional than humans. Maybe they think that's better; or, maybe they've lost something and wish they still had it.
I say all of this because of the weird emotion recorder that Narim gave Sam. What's up with that? He couldn't communicate with her directly how he felt ... he had to give her some silly device. I'm sure that's normal in their world (though Narim seemed frustrated with not being able to communicate more successfully with Sam), but it's pretty freaky in ours. Possibly an indication of a trade off that may ultimately come with advances in other areas like increased technology.
Would we give up our capacity to communicate love or to have empathy in order to be able to travel to other worlds or record emotions?
As is typical with about every episode of Stargate, there was some inexcusable retardation. Number one: that such an advanced race would leave behind ten or twenty people for the dubious reason of burying the stargate. How's about burying it with your technology in about two hours and then getting the heck outta Dodge before Vesuvius pops its cap? Coming up with a legitimate explanation for why those select few were the only ones left would not have been that difficult.
Number two: the Tollan's clothing and gadget designs were so cliche and so stupid. Why, of why, must so many alien races or technologically advanced peoples wear silly metallic uniforms that are begging to show off camel toes and stuff? And considering their technology, would they really wear such bulky, plasticky boxes all up and down their arms? They can walk through walls and send a messsage within a few hours to the Nox's planet which is probably millions, if not billions of light years away, but they can't explore the concept of miniaturization of their Blackberries and what not?