You ain't offending me. But, Spectre did not do most of the work. Hal was half way rid of Parallax and at that point, he asks for help. Spectre couldn't get rid of Parallax himself and since we seem to be in agreement on at least that, how can you give him more credit than Hal?
Second, the reason why the JLA, Titans, JSA and 3 Lanterns couldn't hurt Parallax-infected Spectre/Hal wasn't because he was more powerful at that time. It was because they didn't know HOW to fight it. Thats why a mere 5 Lanterns were able to take down P-infected Ganthet. They understood it and they used their rings as a conduit to trap Parallax.
For the theory of Spectre > Ganthet, you MUST assume these premises:
1) Ganthet is lying OR doesn't know what he's talking about.
2) Parallax is contradicting himself just so he can mock Ganthet.
3) The drama placed on Ganthet's possession derives from a love of the character rather than an emphasis on more danger.
4) The climax was written so that it was at its peak danger during issue #4 and lowered the stakes by #5-6.
5) The writer's and artist's designs were misleading.
For Ganthet > Spectre, those same premises are presented this way:
1) Ganthet is not lying AND knows what he's talking about.
2) Parallax never contradicts himself.
3) The drama from Ganthet's possession derives from a heightened crisis due to an increase in power.
4) The climax was written in #5 and #6 right before the resolution.
5) The writer's designs and artist's renditions were correct in making infected Ganthet much more massive and monstrous and intimidating.
Do you see where I'm getting at and why I'm getting there? Its the idea of Okham's razor. If its easier to explain it in one way, the reason is because that is the way it probably is. You're theory runs something like; Ganthet is an idiot, Parallax goes around making fun of people, the writer doesn't know basic story-telling and the depictions are flawed.