Drake Bell is furious with Hollywood for keeping the doors wide open for those who defend abusers -- calling out actor Taran Killam as a prime example.

The former Nickelodeon star -- who bravely shared his sexual abuse allegations against ex-dialogue coach Brian Peck in "Quiet on Set: The Dark Side of Kids TV" -- posted a pic of Taran on his TV screen with the scathing caption, "Write a letter defending an abuser and Hollywood will always hire you."

The pic showed Taran in a scene from ABC's crime drama "High Potential" -- which just got picked up for a second season. Taran's also famously known for 'SNL' and even popped up on the show’s 50th-anniversary special over the weekend.

As we previously reported, Killam was among several A-listers who vouched for Peck during his 2004 sentencing -- defending the convicted child molester’s character and pushing for leniency.

Other big names who backed Peck included James Marsden, Robin Thicke, and "Boy Meets World" stars Will Friedle and Rider Strong -- though the latter two got publicly called out by Drake, prompting them to apologize.

Peck was ultimately sentenced to 16 months behind bars and required to register as a sex offender.

We reached out to Taran's rep ... so far, no word back.