Skandelon,
Your problem is that you don't understand what these calvinist writers are saying. If they believed that Christ was the propitiation for every single person that has ever been, then they would say so, and they don't. Moreover whatever you may say, If Christ were the propitiation for every single person, then God would be propitiated with regard to every single person, and Clearly He isn't. 'He who does not believe the Son shall not see life, but the wrath of God abides on him' John 3:36). Otherwise you would have to say that there is something defective in the propitiation made by Christ because it hasn't worked.
What Hodge et al are saying is that there is no lack in the propitiation made by Christ. No one will ever come to Him in repentance and faith and be told, "I'm sorry! You can't come in. There just isn't enough blood to go round!" All who come in that way will be saved (John 6:37). To quote Dabney, 'Christ's satisfaction is not a pecuniary equivalent, but only such a one as enables the Father, consistently with His attributes, to pardon, if in His mercy He sees fit.'
Now, what does 1John 2:2 mean? There are two possibilities consistent with other Scriptures.
1. The Lord Jesus, by His suffering and death, has propitiated God towards men and women 'Of all nations, tribes peoples and tongues' (Rev 7:9).
2. The Lord Jesus has propitiated God towards the world in which we live. It was cursed in Gen 3:15 (cf. also 5:29). The sacrifice of Noah in Gen 8:20f prefigured the suffering of Christ and so God promised not to estroy the earth. However, although the world is still subject to 'futility,' 'The creation itself also will be delivered from the bondage of corruption into the glorious liberty of the children of God' (Rom 8:20-21. cf. vs 22-3). When Christ returns, not only will we receive new resurrection bodies, but so will the creation (2Peter 3:13 etc.). Then the curse on the earth will be no more (Rev 22:3).
Personally, I favour the second suggestion.
Steve