Why should the Democrats do anything the repubs are whining about when they got zero cooperation from trump and his toadies? trump just uses people and throws them under the bus when they don't bow to his wishes. The Dems chose not to go to court because it got them nowhere when they tried to subpoena Don McGahn. McGahn defied a subpoena last May and months later everything is still tied up in the courts. The repugs could have let him testify but they were afraid to, after McGahn stood up to trump and threatened to blow the whistle on his behind the scenes behaviour.
You've chosen to ignore everything trump said and did about Bolton testifying. And you're just lying to yourself that everything pertaining to Bolton's testimony is the Dems' fault.
"The House
did ask Bolton to testify But Bolton, who
left his post in September,
declined to do so at the
White House’s directive. The White House successfully
blocked a number of officials from testifying or producing documents relevant to the House’s investigation.
Bolton signaled that he would testify only if he were subpoenaed and if a court ruled that he should obey the subpoena over the White House’s instructions.
Bolton’s lawyers said he would sign on to a lawsuit filed by his deputy, Charles Kupperman, who asked a court for guidance after he received a subpoena from the House and an order from the White House not to comply."