There will be lots of useful stuff said about this, but it is unlikely that you will get a clearer explanation of what Sydney is doing, from Sydney's perspective, than the ones given at the briefing here.
In it, Phillip Jensen says:
There is little in the New Testament to encourage Christians to split or divide. In fact we are
warned against the divisive person. The works of the flesh include “rivalries, dissensions, divisions,” (Galatians 5:20). So in the context of foolish controversies dissensions and quarrels God says: “As for a person who stirs up division, after warning him once and then twice, have nothing more to do with him, knowing that such a person is warped and sinful;
he is self-condemned.” (Titus 3.10-11).
...
But this treatment of the divisive person raises a paradox for us. For we are to divide from the divisive person.
These observations are merely an extract from the introductory comments. There is plenty more there to consider, and it will repay careful study for those with an interest in the issue. In particular, Phillip considers many of the New Testament passages that deal with controversy, tolerance and false teaching.
Phillip concludes:
I would urge those bishops who believe that unrepentant active homosexuality is wrong not to compromise their own beliefs, the scriptures, the church of God and the holiness of Christ.
If they have already accepted the invitation they should repent and apologise. It is not good to go back on your word. But you should not have given it in the first place. And to reinforce your error of judgement by attending is to make the same mistake as Herod when he executed John the Baptist. Such faithfulness to your word and promise is perverse rationalisation for continued wrongdoing.
To those bishops who go to Lambeth knowing that unrepentant homosexual activity is wrong - your profession of evangelical credentials will always be tarnished. You cannot expect God's people to trust you as you pick and choose which parts of the Bible apply to others and apply to you.
Actions have divisive effects. You are now put under incredible pressure to act on an issue that is not your own choosing. But you cannot avoid the consequences of your action. Attending is to fellowship with false teachers in their wicked work. It cannot help but diminish faithful Christians' confidence in you as a leader. To believe otherwise is a further
illustration of the naivety which leads you to attend.
The pragmatic arguments of needing to be there to uphold orthodoxy do not wash. By being there you are denying and undermining orthodoxy. You are demonstrating that the issue does not ultimately matter and that these men are the true bishops of the church.
The American bishops believe they are right and wish to change the rest of the church into accepting homosexuality. There is not the slightest indication that they are coming to Lambeth to listen to what the orthodox have to say. This is not the first round of a debate—it has been going on for years. They are not ignorant of alternative viewpoints. They came
last time for the final debate and they lost. They come this time with an action that they refuse to repent of. The American bishops did not listen last time they will not listen this time.
That the Archbishop of Canterbury has invited them only shows his colours. He is on record as agreeing with the American action in principle. Orthodox bishops attending is not going to change the outcome of Lambeth; just legitimise fellowshipping with false teachers or more accurately declare that their teaching is not false.
For our own diocese we need to explain the issues clearly so people will rejoice with thankfulness to God that we are led by Godly bishops who put obedience to the word of God ahead of worldly popularity. It would also be very encouraging to them to be flooded with letters and emails of appreciation at this difficult time.
Strong words indeed. To attend Lambeth is to legitimize fellowship with false teachers—American bishops who insist that homosexual practice must on gospel grounds be accepted as in keeping with Christian love; and Rowan Williams, who by word and action endorses the principles the American bishops are holding to.
Whether or not we see more orthodox bishops decide to take action remains to be seen. Anglicanism does not have a good track record in producing decisive bishops. But I'm thankful to God that some who aren't bishops, such as Phillip, are able to speak with courage and clarity about these things.