Out of combat, right-click on minimap blips to open a targeting menu. This is intended to be used by those classes with tracking capabilities, like hunters and feral druids in cat form. Just to be clear: this cannot work in combat.
MinimapTarget comes with an MinimapTarget_Decorator, an optional module that adds class, level and reaction information to player and pet menu entries. Data are passively gathered from guild roster, party/raid roster, battleground scoreboard and when the mouse hovers over characters and unit frames. This module can be safely disabled at character selection screen.
Please report any issue using the wowace ticket tracker. Please actually check existing tickets to avoid creating duplicate ones. Please include detailed description of the issue, including were you where, what you wanted to target, and if you were using a minimap addon. Also make sure you enabled Lua error reports and are reporting any error message related to MinimapTarget.