This is crass racism. Just like the restive South of Thailand where the Thai Buddhist are vehemently and violently opposed to the Malay Muslims being there, so too in Myanmar, the Bama Buddhists are as violently against the Rohingya Muslims being there in Myanmar. The Bama Buddhists and monks "believe deeply the dark-skinned Rohingyasa are illegal immigrants (from Bangladesh)aggressive outsiders who will steal land from the Buddhist folk". The monks will join in to support any offensive against what they perceive to be threats against ethnicity, religion and motherland.
The perception of these monks are that these Rohingyas are "enemies",who are threatening the safety and livelihood of "their friends" and "their people".Prejudice,disharmony and violence always begin with holding and clinging strongly to concepts and projections of people based on labels. Dualistic perceptions make us create "we-they" divides.
Buddhist monks hold over two hundred vows.Besides the basic Buddhist precept of "non-harming", aren't there vows regarding "kindness" and "compassion" towards all mother beings that they have to hold? If they had cultivated true compassion,they would have already embraced the equanimity of all beings, the equal right of every mother being to pursue life and happiness and to avoid all pain and suffering.