Actually, I think you're off by one...

Tiagra is still in the recreational line while Deore crosses the line into performance...

If you read Shimano's descriptions, they list the Deore as 'performance' and compare it to the higher, performance lines they carry. The description for the 105 is almost identical except they compare it to Dura-Ace and Ultrgra instead of XT and LX.

Meanwhile, the Alivio is described as "quality recreational" while the description for the Tiagra is similar.

I think you are off by one:
Acera/Sora -- Recreational
Alivio/Tiagra -- High End recreational
Deore/105 -- Low End Performance
SLX/Ultrega -- Performance
DA/XTR -- High Performance