God has given the Salvation Army a charitable nature and blessed it with members who similarly want to be 'like Jesus' who himself went against the conventions of the day to become involved with people who were poor, sick and rejected by society.
Rather than narrowly home in on doctrinal differences would it not be better to embrace the Salvation Army within your own thinking as a part of God's gift to humanity? I'm sure Christ himself still welcomes the adoration and honor given to him through the ministry of the soldiers of Christ, known as the Salvation Army. Equally, God is surely raising His hands in despair at the petty arguments among Christians about liturgy and doctrine when we should all be telling and showing the world about the love of Jesus and how he can change lives.
Forget the differences and embrace the mission!
"I marvel that you are turning away so soon from Him who called you in the grace of Christ, to a different gospel, which is not another; but there are some who trouble you and want to pervert the gospel of Christ. But even if we, or an angel from heaven, preach any other gospel to you than what we have preached to you, let him be accursed. As we have said before, so now I say again, if anyone preaches any other gospel to you than what you have received, let him be accursed. For do I now persuade men, or God? Or do I seek to please men? For if I still pleased men, I would not be a bondservant of Christ" (Galatians 1:6-10).
It is sad to see people who think they know exactly what God wants without ever asking Him. You state that the Salvation Army is God's gift to humanity, but the denomination did not come from God. It's doctrines are loosely based on teachings found in the Bible, but they do differ from those found in the Bible. You state that you are sure that Christ would welcome adoration and honor from these people, but it was Christ himself who scolded, "Hypocrites! Well did Isaiah prophesy about you, saying: 'These people draw near to Me with their mouth, And honor Me with their lips, But their heart is far from Me. And in vain they worship Me, Teaching as doctrines the commandments of men'" (Matthew 15:8-9). Oh, but wait a minute! You said God is despairing over petty arguments about doctrine and here Jesus just scolded people from substituting man's commandments for God's doctrines. He used the nasty 'd' word (doctrine)!
The fundamental flaw is your bold assumption that you know what God wants and what pleases God. "For what man knows the things of a man except the spirit of the man which is in him? Even so no one knows the things of God except the Spirit of God. Now we have received, not the spirit of the world, but the Spirit who is from God, that we might know the things that have been freely given to us by God. These things we also speak, not in words which man's wisdom teaches but which the Holy Spirit teaches, comparing spiritual things with spiritual" (I Corinthians 2:11-13). The only way we know what God wants is by understanding what God said -- not what you think God meant, but what God actually said. Then, when we follow God's teachings (His doctrine, if you can bring yourself to say that word), then we demonstrate our love for Him. "If you love Me, keep My commandments" (John 14:15). Do you really, truly love God? Then why are you so willing to ignore what He has commanded and taught? How is God being honored when the organization being advocated is man-made in organization, doctrine, and action? "By this we know that we love the children of God, when we love God and keep His commandments. For this is the love of God, that we keep His commandments. And His commandments are not burdensome" (I John 5:2-3).
Somehow you have it in your mind that if a person stands up and proclaims the doctrine of God, that somehow God doesn't want that to happen. "Beloved, while I was very diligent to write to you concerning our common salvation, I found it necessary to write to you exhorting you to contend earnestly for the faith which was once for all delivered to the saints" (Jude 3). Paul warned Timothy about people like yourself. "I charge you therefore before God and the Lord Jesus Christ, who will judge the living and the dead at His appearing and His kingdom: Preach the word! Be ready in season and out of season. Convince, rebuke, exhort, with all longsuffering and teaching. For the time will come when they will not endure sound doctrine, but according to their own desires, because they have itching ears, they will heap up for themselves teachers; and they will turn their ears away from the truth, and be turned aside to fables" (II Timothy 4:1-4).
Unity only comes in standing behind our Lord and King. You might think it doesn't matter whether you follow the directions of your Master, so long as your intentions are good, but if you know anything about warfare, you know that no army could survive second-guessing the commands of its general and each unit going off to do things its own way as it sees fit.