Arduino micro lost connection after first programming
The USB part of the Atmega32U4 needs quite a bit of software to operate correctly, which is either not included in the basic blinky example or you got a binary for a different Arduino model.

The syslog looks like there is a bootloader present after Reset for a couple of seconds..

[22620.497393] cdc_acm 1-2:1.0: ttyACM0: USB ACM device
     ^
[22627.966141] usb 1-2: USB disconnect, device number 32
     ^


.. which shuts down and starts blinky. This is documented on the ArduinoBoardMicro page.

Re-flashing the chip is a bit tricky in this state, as you must press the reset button at the "right" time just before the software wants to access the chip.