You stated your position on the Slavic ethnicity, not the Slavic languages. If you believe the Slavic languages ultimately descend from the same post-PIE proto-language as the Baltic languages, you believe in the Balto-Slavic theory, even if you don't like the name. If you only care about the present situation, you may as well say there's no such thing as Baltic languages since Latvian and Lithuanian are separate languages. /comhrá