Came to get rid of people with different opinions from their own. Although any involvement is denied.
Although the president has denied any direct involvement, it's widely known the president has poisoned those who revealed classified information, shot journalists, restricted the media, and detained protesters, among other things.
ご質問ありがとうございます。
まず、「自分の意に合わない人を排除してきた」はそのまま英語で「Came to get rid of people with different opinions from their own.」と言えます。
そして、「関与は否定しているが」の場合、「Although any involvement is denied.」になります。
また「本人は関与を認めていないが、大統領の秘密を暴露した者を毒殺、ジャーナリストを射殺、メディア規制、デモ参加者を拘束等々」と説明したいなら、「Although the president has denied any direct involvement, it's widely known the president has poisoned those who revealed classified information, shot journalists, restricted the media, and detained protesters, among other things.」という風に言えます。
ご参考になれば幸いです。
アメリカ合衆国 
