I agree. The difficulty lies in the application.
It astounds me that, of all the things we've discussed, only instrumental music as an accompaniment to singing amounts to a modification of God's command in your view. This is prima facie denominational bias, not based on reason at all.
You're welcome to live according to it if you like, but you must not attempt to hold all of Christendom to this standard.
I tell you the truth, your reasoning puts me in the mind of nothing so much as Matthew 23:16-22. Be careful, brother. Be very careful.
I am glad we agree that adding or taking away from the commands of God is wrong. Now let's look at an example that we have discussed: using the internet to spread the Gospel. Is this adding to the command we are given in Matthew 28:19-20?