The article references having burial specialists. This would require certain people having the right to take deceased corpses and burying without regard for the family/tribal/religious requests/requirements etc. This would at the very least be seen as impinging on the rights of the family, it would likely need armed support. If these burial specialists were say American, they would NOT be deployed without American armed support. Having American armed support (most likely the army) on the ground supporting people who are likely to be impinging on perceived rights will be viewed as trampling sovereignty.
Australia and the Netherlands had a similar issue with the downing of the Malaysian Airliner in Ukraine. In this case, the Ukrainian government had to pass legislation to allow armed Australian and Dutch military to support inspectors. They were just 'inspecting', not creating forced closures of specific areas, forcing burials, witholding care, etc all under significant armed guards.
The present situation on the ground (and the lack of 3rd party government level interaction) is largely a result of weak leadership by the UN. The better question is why the UN hasn't taken ownership of the outbreak?