Yes, the 1st amendment gives the freedom of speech which includes protest.
It was indeed a legal protest
In the US, any public protest is legal, as long as you apply for the appropriate permits for lawful public assembly.
yes
Picket, boycott, speech.
Roman Apostolic Christian is what Lionel Messi is by background
ethnic : Russia religious : Muslim
They have the 1st amendment right to protest on public property, so your answer is yes. Even though they do have the right it seems as if they are not respecting the family of the fallen solider in their protest at the funeral.
US court of federal claims
The right to protest is guaranteed under the US constitution. We all have to support the freedom to protest, even if we do not support the protest itself.
Yes, of course it's legal to petition the US Supreme Court. When discussing Supreme Court cases, it's important to realize "petition" means to file an appeal of a case already decided by the lower courts. It does not mean to send a signature petition in protest or support of a decision. You are within your legal rights to send such a document, but the Court is not required to read it.
we stopped selling them oil
In the US, it's a right.