Yes, repeatedly interrupting ongoing conversations by abruptly pointing at things and shouting "look at that blank" can be considered rude and disruptive behavior. While it may not be intentional, such actions can be perceived as disrespectful and inconsiderate to the other people in the conversation.
Interrupting conversations regularly can make others feel like their input or opinions are not valued and may lead to frustration or annoyance among the group. It's essential for everyone to have a chance to express themselves and be heard during a conversation.
If your friend tends to do this often, it might be helpful to have a polite and private conversation with them about the impact of their behavior on others. Encourage them to be more mindful of their timing and to wait for appropriate moments to share their observations without interrupting ongoing discussions. Remind them that active listening and respect for others' contributions are crucial aspects of effective communication and maintaining positive social interactions.