Latias Ex (SSP) using its own Skyliner ability

I’m new to the TCG.Was playing a control deck using multiple Spidops Ex to increase retreat cost of opponent’s active Pokemon. I Boss’d up the only Latias Ex on the opponent bench. Was ruled that Latias Ex has NO retreat cost due to its own ability. Then I asked why does it have a retreat cost of 2 colorless energy. Didn’t get an answer and just told that even in the active Latias Ex can use free retreat due to its Skyliner ability. So my question, Why does Latias Ex have a retreat cost if it can use its own ability when placed in the active?