No one is going to bring the Dalai Lama "down." Whether or not you do Dorje Shugden practices is not important. All deities, all gods, are concepts created in the mind. They are symbols that we generate with the aspiration that we c an one day embody their characteristics. But they are not real beings. I am Buddhist in both the Gelugpa and Kagyu traditions. I previously was involved with other spiritual traditions that were centered around what turned out to be false gurus, and it embittered me towards spirituality until my refuge lama set me straight. He did not want to hear a single word of complaint about my experiences with false gurus. He said that if I spent so much time with them, then I should have learned SOMETHING!!! And I should be grateful for that. And indeed I am. I learned 2 major things. First, that god lives inside you as you. That is, your concept of deity is just that, a concept that is totally unique to you. No one else can have exactly your concept, because no one else has exactly your mind, perceptions, and experiences.
2ndly, I learned never ever to put anyone on a pedestal -- not even the Dalai Lama. There's only one thing that you can do after you put someone on a pedestal, and that is to knock them off, because they are human, and they make mistakes. So be confident in the dharma, it's bigger, deeper than any one teacher. The characteristics that Dorje Shugden symbolizes are shared by many other yiddams (deities). So it really doesn't matter which symbolic deity you pick, or none at all. What's important is the practice of mindfulness and compassion. If you find that you get value from going to that center, then keep going. If you have the opportunity to go do a different center and learn what those teachers have to teach, then do so. Keep an open mind, take it all in, and be confident that your inner wisdom mind can sort out what to use and what to drop. My 2 cents.