"Festivals are not an important part of religious life."
This is an important statement to consider because festivals are a large part of Islam. They take up a lot of time, effort and money. One must consider the importance of Muslim festivals and other religious festivals as they affect many people, even those not celebrating it.
Ummah is very important in Islam as it strengthens Muslims and keeps them close together, festivals help build the community and strengthen it. A common similarity that runs through Islamic feasts, festivals, and celebrations is the strengthening of social relations among the members of the community (ummah). These celebrations require sharing the joy and happiness, by sharing food and gifts; connecting with Allah and by sustaining ummah. The sharing of the food with those who are less fortunate is a way to show equality and acceptance among the community, festivals are a time when everyone is equal and accepted no matter what rank or status, as they are all celebrating the same thing, e.g. when food is shared in Eid ul Adha and in Eid ul Fitr.
One reason as to why Festivals are not an important part of religious life is that they could be sometimes over publicised and comercialised, this could distract people and stop them from thinking deeply about the true roots of the celebration. In a lot of religious festivals everywhere you go there are advertisements, banners, and images these don't necessarily help people understand the reason behind all the celebration and increase their knowledge. This may give people a "fake" or "artificial" image of what the Festival is really about. In addition this religious festivals may not be open to every one, those of other religions or no religions, this could cause divisions within the multi-religious communities as not everyone can join in.
Another reason as to why festivals are of importance in religious life is that they can be used as a platform to spread out the message of the religion. They can also be fun as they are a time of celebration and happiness, they are something to look forward to and provide a break from everyday work and distractions. Festivals are a time to reflect on the things that matter, a time to devote to Allah (or God) and to think of those less fortunate. They can be a time for looking back on experiences such as when on Eid ul Fitr Muslims celebrate the completion of Ramadan and Eid up Adha when they look back and reflect on their Hajj experience and celebrate the end of Hajj.
Festivals, if poorly managed, could lead to food wastage, such as at the end of Hajj when a sheep is sacrificed the food doesn't always make it to the needy and due to poor management sometimes could end up in the bin. Therefore wasting a lot of money and Allah's creation.
Religious Festivals can be great as they are a way to connect with friends and family, even those that one hasn't seen in a while. They provide a time for connection with Allah/God and are a time to be happy and separate from day to day life, to think deaply of meaningful things. This is why religious festivals are an important part of religious life. They can however be wasteful and cost a lot of money. They may provide distractions and be overly publicised in a "fake" way hiding the reality of the religious celebration.