You don't need to go shouting it, but if someone starts talking politics at you, fucking own it. Some coworker is like "trump sucks", say "yeah I know, I'm a communist". Your grandpa says "trump rules", say "no he sucks ass, I'm a communist". You're on a date and they ask who you're voting for? Say "I'm a communist". Cashier asks would you like change? "Yes, I am a communist".
Be open about your politics and lay claim to the title. Be a communist.
You're right - swap out Marx for something like "the fact everyone knows to be true, that there are rich fucks controlling politics and the economy instead of the people as intended"