But surely an advanced civilization would realize theres less advanced lifeforms and would thus send the simplest type of message possible. After contact is established, they could then send their ultra-compressed data.
For a civilization to survive and be qualified as being advanced, not only implies being smart enough to develop some technology but smart enough to know when NOT to use it. e.g.: let's not use nuclear warheads, let's not use grey goo, let's not communicate with possibly agressive alien civilizations.