Weather unions would be anti stock option or not is debatable, certainly not a fact, and the tweet is absolutely clear cut a threat that workers would lose them if they unionized independent of what the union would do.
Can you cite any instance where a union representing blue collar workers has negotiated stock options or similar stock based compensation as part of their member's pay package?
Can you cite any instance where a union representing blue collar workers who already have stock options or similar stock based compensation as part of their member's pay package has lost them in negotiation?