By Sheila Dang and Katie Paul (Reuters) – Major tech companies on Thursday committed to taking fresh steps to combat online extremism by removing more violent content and promoting media literacy with young users, as part of a White House summit on fighting hate-fueled violence. Platforms like Alphabet’s YouTube and Meta Platforms’ Facebook have come under fire for years from critics who say the companies have allowed hate speech, lies and violent rhetoric to flourish on their services. U.S. President Joe Biden earlier on Thursday called on Americans to combat racism and extremism during a sum…