Yes Starbucks just like any other buisness establishment has an opinion and has the freedom of speech. If the Starbucks company wants to make a political statement then they have the right to do so. People may agree or disagree. It may cause more buisness or less buisness but its their choice.
No, Starbucks should not make political statements. As a company, it has the right to have freedom of expression or speech but the owners should refrain from making political statements, to avoid offending their customers. Starbucks customers believe in many political ideologies and they might take offense if Starbucks was to take a stand on an issue, that they disagreed with. If they were to upset their patrons, they might lose revenue and face boycotts thus it is best for them to remain out of the political scene.
Why a company that exploits the labor of coffee bean farmers feels that they have some moral high ground is a mystery to me. Starbucks over chargers for low quality coffee. They also systematically squeeze out Mom and Pop coffee shops. They need to stick to their bland, generic coffee.
I don't believe the rumors that they were sending money to Israel, but in any case I don't think businesses should be involved in the political sphere. They should not have any influence in that arena and vice versa. I think the truth will come out and we will see that starbucks is innocent