QB Issue Resolution:

These Donors cannot be deleted permanently like you said, but yes, there is a way to hide them. First click Donors on the left navigation panel. Click the small Gear icon above the Action column. Un-check Include Inactive at the bottom. I have attached a photo for clarification.

Resolution for Issue 'How do I remove a deleted name altogether from our Donors menu?' available: Yes (Solved).
Source: Intuit Community forum.

How do I remove a deleted name altogether from our Donors menu?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for altogether
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!

Error Recovery for altogether [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.

Get 50% off Quickbooks Online

Click Here for 50% off!

Additional Support Options: