Ruling question - Why Steelswarm Roach could not activate its effect?

[Dr.E.Cat *=_VF_=*]

Replay link:
https://duellinks.konami.net/att/00bad6889073f1c6276d011346e4b8e46c9431428b

I had Steelswarm Roach on boarh when my opponend pendulum summoned Mayosenju Daibak. An option to negate the summon was not shown. I don't understand why - it is a special summon and the monster level is above 5. Can someone explain please?

[DUBINA]

read your opp's cards. you cannot negate pendulum summon of daibak.