I use a chain tool and have removed pins to 'break' the chain many a times for each chain. I never thought/knew/heard it would ruin the chain...if that's true then people wouldn't reuse chains over and again after doing maintenance.
Ive broken one chain probably 8 times alone in the past couple months while working on building a vintage bike up from scratch. The chain is new and is sticky at the point where the pin is reinserted, but some simple lateral movement and the link frees up.