No, it's not like that, it can be read on normal days as far as I know. The Garuda Purana has a part known as preta kalpa which describes the journey after death and the related rituals to be done. Those are referred and read during the occasion of the passing away of someone. So it has become a taboo or fear to read it on other days like it has happened wth the sentence "ram naam satya hai" (Rama's name is truth).
So at different places of the purana it has been praised and suggested to read as it offers punya and bestows desires. For example, consider the following verse:
tat śrīmadgaruḍaṃ puṇyaṃ sarvadaṃ paṭhatastava [GP - 1.3.9]
- That auspicious Garuda purana when read gives punya and all objects
taduktaṃ gāruḍaṃ puṇyaṃ purāṇaṃ yaḥ paṭhennaraḥ
sarvakāmamavāpyātha prāpnoti paramāṃ gatim [GP - 1.240.34]
That man who reads this auspicious Garuda purana attains the supreme destination having obtained all his desires.
Given the nature of the subject matter that the purana contains, some portions of it may be considered as inauspicious by people, but I have not come across anything that forbids its reading. In fact at many places it has been praised and suggested to be read as mentioned in the above verses.