That would be true if we take the Holy Tradition to mean anything, which it doesn't. If you want to learn more here is a good summary of the Church Tradition (Orthodox view) this as well as this article.
The Holy Tradition is timeless and unchanging. It includes the scriptures, the patristics, the (seven) ecumenical or general councils as its major components, as well as the Symbol of Faith (in the West otherwise known as the Creed), the Divine Liturgy (going back some 17 centuries), and the canons of the Church. In other words what the Church did and what she believed all along, or simply how she lived out her faith.
By unchanging they don't mean that nothing ever changes (vestments, hymns, typikons, etc.) but the faith. The Eastern Church believes that what it believed today was believed yesterday and all the way back as far as the Church goes and that all that was believed was in harmony with its Holy Tradition.
Thank you for the link. The more I read about the Orthodox Church, the more I like it. The EO, I believe, has stayed a lot more faithful to the word than the “you-know-whos”. :o)