Explain the rationale behind granting the right of removal to both parties in a case

What will be an ideal response?

Right of removal allows a case filed in a state court to be moved to a federal court if the case falls under concurrent jurisdiction. A case must involve diversity of citizenship or a federal question to be categorized under concurrent jurisdiction.
In certain cases, a party may fear local prejudice in a state court. Juries for a state court are generally drawn from the county in which the court is located. The juries for federal district courts are drawn from the entire district, which encompasses many counties. Juries in state court are, therefore, usually more homogeneous than those in a district court. One problem that this homogeneity may present to the out-of-state corporate defendant occurs when the county in which the court is located is predominantly rural. If the case involves an injury to a member of this rural community, the defendant may feel that the rural jurors would be more sympathetic to the local injured party, whereas jurors drawn from a broader area, including cities, may be more likely to view the victim less sympathetically. City residents are also more likely to work for a corporation, and thus may not regard corporations as unfavorably as might rural residents.
Some people also believe that federal judges are better qualified to hear cases that involve a federal question, because they have more experience in resolving questions that require an interpretation of federal statutes. Finally, if a party anticipates that it may be necessary to appeal the case to the U.S. Supreme Court, bringing the case first in a federal district court may save one step in the appeals process.